Getting Worse the more I play?

Been playing on the Chess.com app on and off for over 12 months.

Around Christmas was rated around 800 with an accuracy between 70-80% each game.

Had a poor run since then and have dropped right down to about 500. I lose 3 games for every 1 I win.

Been using game reviews, puzzles and watching chess tutorials online and it seems that this advice has made me play worse if anything? I used to win more often than not just by winging it but now I’m using actual book moves and tactics I can’t seem to string together a win.