I would have called it Abstract Black on Black.

Sorry, looks like you already used Black on Black

I like the first one best.
Have you tried any Milky Way shots? Today and tomorrow should be good nights for it if you know where to point your camera. Get a phone app like Photopills to tell you the time direction (Azimuth) and height (Elevation) for best shot at your location. Depending on how much 'dark sky' you have you may not be able see it with the naked eye. Use the compass and a level app to set the camera up on your tripod and shoot.

Another vote for Breakthrough. Excellent quality. Also, I like that the ring has a knurled edge which makes it easier to rotate the filter while the lens hood is on.

For a lower priced alternative look at the filters from Urth.co. I hadn't heard of them until recently and was persuaded by the reviews I came across to give them a try. I didn't try their CPL, but I have been very impressed with the quality of their ND filters - at about half the price of Breakthrough or B+W

To answer your question(s)

I don't use the LCD screen much for manual focusing, but the Electronic Viewfinders (EVF) are very good. Most (if not all) mirrorless offer a 'focus assist' ability that will enlarge the image in the EVF by 100% - 200% so you can get the focus pin sharp in the viewfinder. They also have a live focus 'peaking' feature which can be used to illustrate the depth of field in the viewfinder. However, the focusing on the newer mirrorless is so good you may rarely need to manual focus. 'Eye' focus or 'Animal Eye' focus will automatically focus right onto the eye of your subject instantaneously and with a high rate of success.
A benefit with mirrorless that is not often mentioned, is that once you have the diopter adjusted to your eyesight, you can review your shots and call up all of the menus and adjust settings in the viewfinder (EVF) without having to mess with reading glasses to 'chimp' to the LCD screen.

Call the computer ‘experts’ at B&H. They can advise you on the best bang for the buck for your photo needs. Take advantage of their tax ‘free’ or interest free loans and great service.

If it not overcast or there is no open shade, wait until evening. If you have to shoot in mid-day open sun, fill flash may be your best option, but you need to get the hang of it beforehand.

One of the things that distinguishes great lenses (ie expensive) lenses from other lenses is how they perform in the corners and edges of the frame. Since the crop sensor will be cropping off the edges of the image, there is no (or not much) point in paying a premium for the edge performance of a high end FF lens over a middle of the road model.

Nikon will catch up to the current Sony’s - eventually! By then, Sony will be even better and you will be in the same dilemma.

Contact one of the computer experts at B&H. They are photography savvy and can advise you on the best set up to meet your needs and budget.

Just dial down the Exposure Compensation until you get it to look the way you want it in the EVF. That's what EC is there for.

If you want the computer primarily for photo editing, try contacting one of the computer experts at B&H. They will give you good solid recommendations to suite your needs and budget.

https://www.bhphotovideo.com/find/shared/experts-profiles-all-categories.jsp

Were you wearing glasses when looking through the EVF? Is so the gap between your face and the viewfinder may have been allowing the bright light to wash out the view. Try adjusting the diopter on the eyepiece so you can see without your glasses.

Tom Brady has started an NFT company that will specialize in sport star autographs.

If I was some sort of celebrity staying at a fancy hotel, I wouldn't want want someone with an A9 and a 600mm lens wandering around the grounds. In fact, I don't think I would be comfortable about it even though I am not a celebrity.

Here is a site that tries to apply some science to evaluating and comparing tripods.
https://thecentercolumn.com/rankings/