The anarchist library is pretty good if you're interested in anarchist theory.
The FAQ is a great starting point, I'd recommend jumping around though, it's easier to get specific answers than reading straight through imo.
The librarian picks would also probably be a good place to look, one of the recommendations there is Emma Goldman who is great.
I think the backpain part is true, according to people who know him it was a surfing accident. His reddit account also talks about chronic pain and complications from that, like brainfog.
Yeah, it kinda sucks how cloud reliant most smart watches are. Like other people in the thread mentioned I think stuff like the pine time, bangle js, etc are probably your best bet for cheaper ones.
There's also asteroidOS which you can flash onto certain older smart watches. It's what I'm currently using but there isn't as much support for it so for more complicated data tracking would require setting up something like a raspberry pi to periodically fetch data over Bluetooth and process it yourself.
https://www.crowdsupply.com/protocentral/healthypi-move
This is a project I've been interested in for a bit. It looks like it will have a pretty good feature set out of the box, and with everything about it being open source I'm sure there will be an API for it at some point too. The price is a bit on the expensive side but is honestly pretty comparable to most current gen smartwatches tbh.
I actually kinda feel that someone like Bernie may have had enough youth appeal to have a somewhat organic version of that happen. During the 2016 primaries, a decent amount of memes and online talk were spawned by him/his campaign.
Definitely agree that delivery is extremely important though, campaigning on helping workers while appearing elite and out of touch just makes people consider you a liar or to be looking down at people.