Surprised how different blitz is compared to rapid

So recently I've reached 1100 elo in rapid, which from my understanding indicates that I'm a decent beginner(?) So after that milestone, I decided to start playing blitz as I was 600 elo until I've reached like 700-800 or something. Now what I had expected was a couple easy walk-in-the-park-hikaru-style games (My mindset was that I was a 1100 against 500-700 players) but to my surprise, that wasn't nearly the case and I was actually taken aback by how "decent" my opponents seemed to be. Being tilted, of course, I played even worse in the last few games. After that I did some googling and found out that it's apparently common to be good at either rapid or blitz and suck at the other. Now here comes the point of the post. To veteran blitz players who are really good, what are the most important tips you think matter a lot when playing blitz that are not just summed up in "Keep playing until you improve Lol"?

Blitz ratings are usually lower than rapid ratings at your level, but as you rise through the ranks the blitz becomes higher.

I'm in exactly the same spot and trying to figure it out. I think it's that I take too much time even though usually I end up going with a move I saw in 5 seconds or less, or because I pick a variation that's I know I could defend in rapid but in blitz I can't defend the same way I can in longer time control. Maybe if I limited my calculation to maybe 2 moves with a blunder check I'd improve at blitz but I'm only playing blitz recently to speed up so I never feel rushed in rapid so I feel like that would hinder my growth overall I'm not going to fully commit to speed