I believe puzzles to be one of the absolute best ways to learn chess tactics and overall strategy. Of all the things to do in Chess also one of the most addicting, I've done 819 of them but usually do a few hundred at a time. Today I hit a new personal best of 1009 rating, my previous was 847. This could mean it's possible I play Chess around that rating at moments. I also do a bunch of these on Play Magnus Tactics Frenzy app, really fun mobile method. Just FYI I play the chess bots rated at 1100 almost daily and win 40-50% of the time, so that seems to work out numbers wise. 1200 gets quite a bit tougher, I lose most games vs those bots.
Sometimes the puzzle is just a quick mate in one, sometimes best defensive move, sometimes it's 5+ moves to checkmate. You study the puzzle and figure out what's going on first, usually if your king is under threat of mate you have an attack that "forces" a move by the opponent. Forcing moves are super duper important and take all the attack away from your opponent and often times just totally eliminates their threatening pieces in the process.
As I got closer to 1000 the puzzles did in fact get more tricky, it's like adding a few more levels of thinking and not so simple to see. I noticed more capturing of bishops was the entire goal or even a simple best passed pawn path was the puzzle. If my head was to ever start smoking from all the processing it would be on those not so obvious "black to move" turns.
Studying then playing a few live opponent games seems to be working good for me, some days I'll play a bunch of games but will get tired and start the stupid crap. I think I'll start playing 30 minute games too, more thinking more learning.
After doing the puzzles I went and faced off against "Mr Beast" a celebrity bot rated 1100 and totally destroyed. I have been playing this particular bot a bunch lately because it seems harder than normal 1100 ranked bots imo.