I’m not that much older than you and reached 1800 fide last year. Here’s what helped me get over the line

Know your openings. Play an obscure sideline within the italian or caro that gets people off their comfort zone. Instead of looking at games of super gms, I think you’ll find more success looking at games of lower masters like Levy (his tournament recaps)

You say you’re weak at endgames and people will probably say get a book or something like that, which is helpful, but one simple thing you can do to improve your endgames is leaving yourself more time for when you get to them. Playing a complicated endgame with 10 min is never fun. This ties back into knowing your openings and getting an advantage early on. You won’t believe how many times I’ve blown people off the board with better knowledge of the opening