Always loosing on time in 10 min rapid

Playing more 15|10 games, a lot more mind you, will translate to getting better at faster time controls over time. It's better to play classical for this though. Good luck.

Quickly eliminate obviously bad moves, narrow your choice to 2-3 plausible moves, then compare them more deeply.

or go to 3 minutes game..play a while and then return to 10 minutes..you will see that you have plenty of time

If I am playing classical chess, I‘m quite good. Because Ive been playing chess just for a few months now, I simply need much time to think. If I play classical chess I often use the explorer to analyse the game and plan my next moves.
But I am very annoyed, that I am that „stupid“ when it comes to fast playing….