best time limit to learn

Yeah, 3 minute blitz isn't enough time unless you already have a fair amount of experience.  When you have internalized all kinds of patterns the way titled players have, then it's fine.  The rest of us end up "perfecting" our mistakes and don't get better.  I'm not a fan of classical slow games for learning either.  Relative beginners run out of stuff to think about pretty quickly.  I think the rapid games (15/10) are the ideal format.  They don't take forever, but do give you time to think and if you end up in time trouble, you can always live off the increment.  If you really don't always have time for a rapid game, then 10 minute blitz is OK now and again, but it really doesn't give you enough time to figure stuff out the way rapid does.  My $.02...

I play daily and 30 minutes. Are you reviewing your games afterwards? It's good to be able to allocate another 15-30 mins to analyse your game yourself, not using the engine. Try to spot tactics you missed, find better moves, work out the move(s) where it went wrong, or alternative lines at turning points in the game. This helps you find and correct bad habits. So 15/10 or longer and allow 15 to 30 minutes for post match analysis. This might mean 1h to 1h30 per game. You dont have to play every game like this if you enjoy blitz, but try to set some time aside for long controls and analysis every week. Finally, it can takes me at least 3 minutes to solve a 1400 chess puzzle. My guess is you are missing a lot of tactics.

Yeah as @Ata comments, do you have much time to calculate, visualise, evaluate and make medium term plans or are you largely playing move to move? These are important skills that may go undeveloped, or develop much slower, if you play a lot of blitz.

Play Longer Time Controls...

For many at the beginner-novice level, speed chess tends to be primarily an exercise in moving pieces around faster than your opponent while avoiding checkmate, in hopes that his/her clock runs out sooner than yours.  Or being fortunate enough to be able to exploit your opponent’s blunders before they exploit yours.

There is little time to think about what you should be doing.

It makes sense that taking more time to think about what you should be doing would promote improvement in your chess skills.

An effective way to improve your chess is therefore to play mostly longer time controls, including "daily" chess, so you have time to think about what you should be doing.

This is not to suggest that you should necessarily play exclusively slow time controls or daily games, but they should be a significant percentage of your games, at least as much, if not more so than speed games which do almost nothing to promote an understanding of how to play the game well.

Here's what IM Jeremy Silman, well-known chess book author, has to say on the topic...
https://www.chess.com/article/view/longer-time-controls-are-more-instructive

And Dan Heisman, well-known chess teacher and chess book author…
https://web.archive.org/web/20140627052239/http:/www.chesscafe.com/text/heisman16.pdf

https://www.chess.com/blog/RussBell/dan-heisman-resources

and the experience of a FIDE Master...
https://www.chess.com/forum/view/general/how-blitz-and-bullet-rotted-my-brain-don-t-let-it-rot-yours

Try out different time formats. As some have already said beginners quickly run out of things to think about so 60+0 is usually too much time for you. Try playing 15+10 here and there and see how it goes. Try seeing checks, captures and attacks for you and for your opponent before making every single one of your moves. Try seeing where all your opponent's pieces can go to in the next move before making a move and where all of your pieces can go to before making a move. If 15+10 is too fast for you to do all this, try a slower time control. Do these games ocassionally and always analize them after you finish them, don't play a lot of them in a row. Keep  playing 3min if you like it.