I would get the 7, or even a 6– what I have. It will get updates for a while and even when the updates stop it should continue to work after that.
One of most popular pages on my blog is about how to replace the battery on Fenix 5.
https://mark.stosberg.com/how-to-replace-the-battery-in-a-garmin-fenix-5-plus-watch/
These watches are made to be repaired. Even after the battery wears out, you can get a replacement for $20 or so and keep it going.
Those are my photos and no- not much I would change. Even bigger loads require electric trikes. You can also chain electric trailers but that’s rare.