Quality over quantity. The longer the games you play, the more instructive they are. You may play more games if you only stick to blitz, but you risk developing habits that may hinder you progress, like flagging your opponent, playing automatic moves such as a3/a6, pinning just because you can, exchanging just because you can, checking just because you can, etc.
Ideally, play OTB classical chess if you want to train calculation and strategy. If you can't, 15 | 10 time control is a good starting point on this site. If you wish to play longer games but can't stare at a screen for long periods of time, you can play correspondence chess (called daily chess on chess.com)
Also longer games are much less addictive.
I decided to cut down on rapid and start playing way more blitz. But instead of just trying to win I try to play the best moves. So even if I lose on time I feel like I’m training myself to find the right moves. Then with blitz you have the advantage of being able to play 3 games in the time you could play 1 rapid and get triple the game reviews for 3 completely different games.
I feel like I’ve progressed pretty well and most of my performance ratings land between 700-900 on average. Is it time to mix in some more rapid and take my time with positions or just keep doing what I’m doing?