You have too many options because you have so much equipment. I have a Z6 and a D500. The latter sits unused because the Z6 is so good, coupling it with Z series lenses. I think that the camera manufacturers have done a great job by specifying which camera is the best for which particular situation. The D500 was marketed as a great camera for action. However, through the three years that I used it and used it extensively, it was great for portraits, still life, multiple images, landscapes - in fact any type of photography that I wanted to do. I was limited by the quality of certain lenses that I owned. I purchased the Z6 last summer and have two Z series lenses. Should I only use this camera for whatever purpose the manufacturer said it was designed for? Bunk - I use it in all shooting situations. I am presently into capturing motion and have done multiple images, zoom bursts, panning, long shutter speeds up to the maximum of 30 seconds (without going to Bulb), etc. etc. Woe is me if someone were to tell me that I must use this or that camera for this or that shoot! I fortunately have the resources to go out and buy more Nikon cameras - I like Nikon. I would love the D850 or the Z7 but when would I use it and why? The Z6 does it all. I do agree that carrying two cameras on a shoot can be an advantage to not changing lenses in the field, whole on a shoot. However, with tripod (tripods?), extra batteries, clothing needs and whatnot, the heavy burden makes for some heavy slogging. I don't know about you but I have a challenge watching over one camera, my extra lenses, my tripod or monopod. Everything seems to drop, not all at once, but in a disordered fashion.

Sirui P-326. It's compact, light yet sturdy. I use my Nikon Z6 with a Nikkor 70-200 mm zoom telephoto. Very stable. I matched the Sirui L-10 head with the monopod. Both pieces are of great quality and they won't 'break the bank'.

A year or so ago, I wanted to go full frame from my cropped sensor D500. My 'walk-around lens was the f/4, 24-120mm. I had never been thrilled with this lens; very heavy and poor quality images except at around 70mm. Since I owned several Nikkor lenses and since there was an adaptor, I purchased the Z6 with a 24-70 f/4 lens. I subsequently traded in most of my F lenses and purchased the Z lens f/4, 14-30mm.
Advantages of Z6 system over the D500 for me: smaller and lighter; Z lenses give sharper results; electronic viewfinder is more informative than the optical view of the D500.
The D500 focused much quicker than does the Z6. Your lenses will 'work' on the Z6 using the adaptor, but auto focus with your lenses will only work if your F-type lens has a motor drive. Otherwise its manual focus time!
I love both cameras. If I hadn't dropped my D500 beyond repair (actually the Black Rapid strap failed), I would still use the D500, notwithstanding my desire to go full frame. I would have wanted to upgrade my lenses but here was the problem. There were no upgrades that were palatable. The f/2.8 lenses were first of all way too heavy and secondly, very expensive. The Z lenses, although not inexpensive, were lighter and as I said before produced sharper images. The weight of the Z6 along with the weight of the Z lenses and the electronic viewfinder have been contributing factors in the improvement generally of my images.

I own a D500 and a Z6. The D500, hands down (whatever that expression means!) is the more responsive (of the two) for action photography.

I must admit that I do not understand the significance of the issue. My photography is based partly upon 'visualization' (what am I looking for - before the image is taken) and part 'whoa, there's an image I want to capture'. I make the decision as I am shooting if the subject is a 'fill the frame' type image or if it should be otherwise. If i have taken the exposure well, I can always crop to convert the image to 'fill the frame'. I am not being flippant;I just don't get it.

There are many variables in selecting the shutter speed to freeze action. In the discussion thus far, ISO has not been considered. With today's amazing cameras, higher ISO settings can be used. I set my ISO to Auto and set the low at 100 and the high at 12,800. The highest amount 'allowed' on my camera is 51,200. There are four basic guidelines about selecting shutter speed to freeze action.
1.Speed of the subject: the faster the pace, the faster shutter speed is required.
2. Direction of the moving subject: subjects from side to side require a faster shutter speed than the subject moving towards or away from the camera.
3. Distance of the subject from the camera: subjects closer to the camera will require a faster shutter speed than subjects further away travelling at the same speed.
4. A wide angle lens requires a shorter shutter speed than if a telephoto lens were used.
After knowing all of this, pick a shutter speed and hope for the best. I think it advisable to err on the faster shutter speed if the situation presents itself.

Thank you all for responding. The user manual provided by Nikon did help me discover the solution. Once the focus has been selected and the focus point(s) in place, depress the 'sub-selector'. This actions locks the focus point where the photographer intended it to be. The manual talks about depressing the shutter half way but this action is useless if the camera has been set to back button focus. I use the AE-ON button for this.
I have not yet tested this 'in the field' but will try to do so later today.
A Happy Covid-19 free day and Mother's Day.

Thank you. I have a D500 and am familiar with the lock mechanism. There has to be something on the Z6 and Z7 but so far I have not been able to engage it.

I shoot with a Nikon Z6. Regardless of my settings (focus mode, metering mode, exposure mode) the focus point does not stay in place, that is, the position in the frame that I set. I no sooner toggle the location that I want it to be, that it decides to move to the lower left of the frame. There must be an action that I can take to fix the autofocus points in place. Can anyone out there assist me. Thanks in advance.

You all need to move to Toronto Canada. We have Downtown Camera, where I primarily shop. Then there is Aden, a small store but very well equipped, also in the downtown business area. There are two chains, each having stores multiple stores in the greater Toronto area as well as outside of Toronto, being Vistek and Henry's. In general camera sales and DSLRs in particular are finding new lows in sales volume, especially during this period of closure. However, the manufacturers are coming out with great product! Retail is likely not a growth industry.

Welcome to our world. I think that there are a number of attributes to cover when purchasing a quality camera. I will list them in some order, not necessarily the most to the least important.
1. shutter lag - once you have selected the scene, what is the delay, if any, in exposing the image.
2. price - my experience is that most any camera that has the minimum features that i would want would be starting at US$ 750. I live in Canada and I think the entry point price is $1,000.
3. If you purchase a DSLR or a mirrorless camera with interchangeable lense capacity, don't get the kit lens. Opt for a good lens that has a wide aperture opening and should be a telephoto zoom. For landscapes, using a crop sensor camera, focal length of 18mm to 135mm or 140mm is good. I'm not certain if you can obtain greater than f/3.5 in this type of lens. If acquiring full frame, definitely go with 24-70. As below, f/4 is good, so long as it is f/4 throughout all of the f/stops. f/2.8 is excellent but typically heavier and significantly more expensive. For low light, I am comfortable with f/4 on my Nikon Z6. I believe that if you were to acquire the body of the entry level DSLRs from Nikon or Canon, your lens should be at lest f/2.8. The lens is the most important purchase that you will make. As you go up the price chain of the camera body, you add features, most of which you will never use. The menu on my camera is filled with options and choices. Im an experienced photographer and for the life of me, I cannot discern the relevance of many of the options.
4. size, weight and ergonomics - a personal choice.
5. Tripod is always an asset when shooting landscapes, but get a lightweight good one. Cost likely around US$ 150.
6. Get a remote shutter release. The ones with a cable are not expensive, likely about US$20.
7. consider a polariser filter - reduce glare and pumps up colour saturation. US$100 or thereabouts.
8. a comfortable and protective camera bag for your gear.
9. Go to a reasonably well stocked camera store. The cameras from Sony, Lumix, Canon and Nikon are all excellent. If money is not an object, go for a Leica!
Good luck

Thank you. I will pass this to my contact at Apple. I'd rather not play with anything for fear of losing photos. This had already occurred with Apple's 'time machine'. I still don't know what this is but I know not to go there!

Hello secular
As part of the overall issue, my hardware was checked by Apple. Apple has acknowledged that the issue is software related.

I may be the 'poster boy' for issues experienced with the Photos program. I have been in discussions with the technical people at Apple since late December 2019. My conclusion thus far is that the issues have only risen recently and a software fix is required but such fix has not yet been developed. You can 'recapture' the image by bringing it up on your screen and click 'edit'. Once the image opens, test which edits you did that have resulted in a grey box. My experience is that I can apply crop but other ones such as 'filter' and 'adjustments' turn the image to a grey box. I have other issues where sometimes the photos program simply is frozen. In these cases I must force close the program and re-open it. I have other issues too frustrating to recount. The most curious is that 'one day' the program works perfectly and 'the next day', it is inoperable. This is a pattern that I have reported to Apple. I must say that the Apple people, in the early stages of my issues, were fabulous. They helped me get to a point where I could use the program effectively, yet experience 'blackout' periods without reason or cause. The se so-called blackout periods happen each time that I use the program, at various lengths of time. At those times, I persist and force close the program repeatedly so that I can complete the tasks that I had begun. Unfortunately for the past month, at least, I have not received any encouraging words or fixes from Apple.

Thank you to all who commented on the bride. AND
The rodeo shot is spectacular - great exposure, sharp as a tack and great timing.