Tips for intermediate players

I have known how to play the game as long as I can remember, but I have only been taking chess seriously for about 2 or 3 months and I can beat all my friends and family who don't play but I cant seem to break past this beginner/intermediate phase of playing. I struggle playing real players online but I can beat a 1000 rated engine with relative ease, I play the london system for white since its lazy and versatile, sometimes the king's gambit but I constantly check variations. but don't have a go to opening for black at all. Where should I go from here? any advice would be appreciated.

I briefly looked at your games and saw that you already play rapid instead of blitz or bullet. Thumbs up! The most important thing on your level is stopping blundering one-move tactics. How can you do that? Do chess puzzles (there are websites where you can do more for free than here) and when you're playing, ALWAYS do a blunder check before you move: are there any undefended pieces on the board? Mine or the opponent's? I would strongly advise you go to YouTube and watch some GM Daniel Naroditsky speedrun videos. There should be playlists for any level. He explains every move and why it's good or bad. How that's gonna help! Cheers