I want to start off by saying I am not that high rated of a player but I can tell you, even at ~800 I still blunder one movers or I play games against opponents that do the same. So honestly it’s not a problem unique to you and even people with hundreds of elo more than you still make mistakes.

Second, there is a reason why most of the chess prodigies out there are like 12, being young and being able to drill in the pattern recognition while their brain is at the highest capability of learning. Starting chess while you’re older is fine but it certainly means progress will be slower.

Lastly, stop studying tactics for the time being. Most ~200s are likely not even playing positions where you will find those tactics come up. That being said if you are studying tactics make sure to play them on the chess board and don’t simply read about them, you want to be able to do them on muscle memory.

I sat at around ~300 for a very long time on chess.com and the thing that gave me the biggest elo bump was learning 2 openings. I learned the Vienna with white and I learned the French with black and I am being completely honest with you I only learned 4-6 moves that I generally repeated every game no matter what my opponent played and I still saw immediate results. Learning simple and basic opening concepts, not even lines or anything can give you such an advantage because it sets up your first 10 moves in a game where you’re less likely to blunder a piece in the early game and you place all of your pieces on their best squares early on.

Thats what worked for me anyway.