How can I improve my chess game?

I've been stuck at 2000 for 40 yrs, but I did have a career and a life. I've picked it up again, and have as a goal, 2200 and a stretch goal of 2400. I'd like to think I could get to 2200 as I have focus now that I am retired. But, I really do not know and I think after a year of serious study, I need to evaluate my opportunity costs as there are other things I like to do.

That said, the on-line puzzles from chess.com or lichess.com are great. Puzzle books are great, better than sudoku, and you have an easy metric to see how well you perform.

Be careful not to play speed chess (its fun) but probably not the best for development.

I recently found: http://www.billwallchess.com/. what is nice, he has a lot of chess books in PGN notation, so you can get the book, then follow thru the whole book on a chess viewer, it saves a lot of time setting up pieces. So, books on endgames, etc are much easier to study.

At the early steps, I'd suggest not to waste time in studying openings and work on combinations, endgames. You just need enough opening to muddle thru and then you can win in later stages.

I am putting together a small binder of the openings I will play. If it is not in the binder, I will not play it. I've been far too whimsical playing things like Kings Gambit, but I need to focus on more specific openings, at least playing them more often.

Tactics, tactics, tactics. Once you get bored of that, throw in one session of studying master games for every nine sessions studying tactics. Later: 10% pawn structures, 10% master games, 80% tactics. Later: 10% pawn structures, 10% openings, 10% master games, 20% endgames, 50% tactics. I think you can stick with this regimen through expert and probably to weak master strength.

Source: peak USCF rating of ~2080

Silmans complete endgame course (book) (good for beginners - experts)

Bobby Fischer teaches chess (book) (for beginner - ~1400)

Always always always review your game after you finish (Everyone)

Review master games:

Agadmator channel (youtube) (might not be helpful if you're a beginner)

There's a bunch of free Chessable videos on master games

Play a lot but pull out when you're in a downward spiral

Josh Watzkins videos were the best. They were in one of the old Chessmaster games, supposedly this playlist has them all but I'm not sure:

https://www.youtube.com/playlist?list=PL1TfIrAqsOzcNSHV00pmv...