Over the years (76 now) I have been trying to go lighter and lighter because holding large, heavey SLR and DSLR cameras and heavy pro lenses has taken its toll. A couple of years ago I traded all DSLRs for an all mirrorless set to lighten the load, and now even these are getting harder and harder to use, so I am even going lighter because I am exercising my hobby lesser ans lesser.

I currently have the canon R6 and R10 with a myriad of RF and EF lenses which have been used less and less frequently nodding to my G7XIII for travel and my (purched used) Panasonic ZS20 for everything else. The ZS20 stays in the car to be available whenever I need to take a photo. These may not take the wonderful photos of the larger (and heavier) equipment, but they are easier on the arms and I can always correct the photos in post processing.

If I were you, in your current situation, (similar to mine) I would opt for the lighter FX1000.

Jack, I haven't owned the Canon but did have the Lumix FZ1000 a few years ago and loved it - great little camera that took excellent photographs. One other thing you *might* want to consider. I recently purchased a Nikon Z50 with Nikon's 18-140mm lens took it to Iceland. The Z50 is an extremely lightweight cropped sensor and the 18-140 lens wasn't heavy to handle. I was very, very happy with the photos it took and the weight. Even carrying it all day, including some pretty strenuous hiking, it never bothered me. As a side note, I'm 66 and have had 10 surgeries on my hands, fingers, and wrists due to arthritis. This setup was never too heavy for me. I know it wasn't one of the cameras you mentioned, but just wanted to throw that out there for consideration.

I have a Lumix FZ1000 II that I use mainly for wildlife photography. It does a great job (so long as I can get close enough to the wildlife), but sometimes I wish that it had more than a 400 mm lens. I considered replacing it (or augmenting it) with an FZ80 or FZ300 to get more zoom, and they get good reviews, but then I realized that they are 5 and 7 years old, and (even thought they are fairly inexpensive) I didn't want invest in technology that old. One of the advantage of the mid-priced bridge cameras is that I can afford to replace them as newer technology comes out. Note that the FZ1000 II is now over 3 years old; so right now, I am watching and waiting for something new to come out.

WRT to the 400mm lens: anything over 400mm starts to get "flat", so it is always better to get closer if you can... but that is sometimes easier said than done when you are dealing with lions, etc.

Also, note that these are much lighter than a DSLR; but they are, by no means, a pocket camera. They take up quite a bit of room in a backpack.