I think you should first find what made you enjoy the game in the first place. Did you enjoy playing with other people? Are getting those good scores making you happy? If your source of happiness from this game comes from something unusual like only playing with hardrock on, then I personally think you should prioritize having fun than improving, even if you aren't gonna be a future top player. What's the point in playing if you don't enjoy the game y'know?
Now for some improvement advice, since you got back to the game again you must be really rusty right about now and aren't playing like you used too. That's normal. What you have to do is to ease your difficulty to the point where you can just be comfortable enough and still be able to feel some challenge. Then you can continue on playing as you used to, but you improve faster during that period since you had experience playing that difficulty before.
Now after you got back to where you were in terms of difficulty, you can start working on your skillset and playing various maps that require various skills, like streaming, jumps, finger control etc. Some players just focus on one skill and that's fine if that's what you wanna do if you feel like it's fun.