Try using chess.com lessons. U can try a free week and see if u fancy it. Why do I recommend it? Because with lessons, puzzles and playing a lot I went from 1200 to 2000 in 8 months. But if u want something different then...
For openings u can try London system. It is very simple, it doesn't have a lot of lines and gives a pleasant middle game position and if opponent isn't familiar with it u can get a nice attack. But for black there is no easy way, but Stafford gambit is an easy and quick way to win with lower rated players, and if your opponents knows how to defend u get at least 2 bishop endgame.
For tactics u just have to do a lot of puzzles, u can use lichess because it is free.
For strategy I would recommend finding a player with your style and analyse his/her games, watch YT videos with that person or follow some streamers.
Hope I helped,
Good luck!
Tactics
Strategy/Positional play
End games
Openings
Right now my rating is around 1100 in chess.com