I feel like I have been shifting through a lot of characters.
I went from being best with King K. Rool to Incineroar, my snake was solid, I went through Ike, and now I am a Roy type.
I still do not have a genuine main, but Ike, Roy and Gandondorf are my closest bets.
Also, you are probably going through that mini-phase where after not playing Smash for a bit, you feel weak. It happens to me. When I have busy weekdays, my playstyle tends to get less better. Just train more, learn new techniques that are useful if you have not, and you will be killing it!