Playing 3 min vs 30 min

Well i don't know your playing style, but in general you grow more as a chess player in the longer time controls. The more time you think about the position on the board, the better your chances are of going beyond just 'patterns'. Blitz and rapid is fun, thrilling, and a skill for sure. But there is joy in realising that a move is good cause it is what the position requires, not just because it's part of a motif you've mastered. I think this level of understanding is easier reached in longer time controls. The longer the better, I'd say... But not so long you get bored 😅
A fair mix across different time controls will be good. But at the end of the day, it's your choice on the time control.
More often than not, a long game has deep, enriched values inside the games since the moves are often thought out to the fullest. However, if you benefit more from watching 3 minute games, it is likely that you are picking up very quickly on general ideas and crucial tactics from these games. Either way, enjoy and have fun playing the games.