How to adapt better to time control changes?

Situation: I am not strong with switching between fast and slow play modes. When you play lots of fast (bullet-blitz) games, you get used to the format and then struggle in longer formats (rapid-classical) by making thoughtless moves. Idem for the other opposite dynamic, playing fast games after lots slow ones makes you lose on time or miss obvious things due to overthinking on deep analytical lines.

Question: How to train smooth adaption to time control changes?

PS. Playing both formats in parallel gives no effect as you end up veering into one direction or another anyway.

I think it works to regularly play different time controls. One way I think helps you to remember what it means to play strong moves is to play correspondence chess. I always have many games going on and make some moves most days.

For me it's a conscious and deliberate piece of mental preparation at the start of every game.

"What is the time control?" is a crucial question I ask myself before I play the first move. If it's a fast one I am then seated forward on my chair in a sort of high-alert mode. If it's slow I'll sit back and gaze more calmly at the board. That seems to work in setting me up to use appropriate thinking time for the game.

Step 1. Just don’t think
Step 2. Play one blitz game then one classical game
Step 3. Repeat