This is a good analysis, and I feel like slower time controls help with checking over hastily-made plans and laziness.
Breaking the Cycle: The #1 Mistake 1200-1500 Players Make and How to Fix It!

I almost never really calculate more than 2 moves deep. I'm too lazy. But maybe it's because I'm relying on the fact that my opponent has the same issue. When My opponent is thinking for a move I often lean forward and think about other things. But I do see my opponent's threats often but I struggle to find good replies. Or in winning positions I just play a move and so something else when opponent is thinking. I know it's wrong but i feel it's a waste of time because I often think I'm better than my opponent or that he will blunder something sooner or later. Or Im completely winning (still lose quite a lot of games when I'm even + 5 according to engine)... They are 'only' 1200-1300 elo right?
Tbh I also mostly rely on tactics(since I have way higher puzzle rating than my opponents in my elo range and also higher blitz rating. Yes my puzzle rating is 1 rn. I tilted because I struggled calculating the puzzles and instead just made a moves and hoped it was right solution.

Thank you for the tip! I thought I was the only one who had this problem... My friends always try calculating during games while i'm like; "Why is he thinking so long to make a move!"

This is a great complement to my own "The Truth Hurts: PSA". Looksgooditis, handwaving on general principles, playing without reviewing, and not evaluating are some key thought process issues suffered by beginners. The first step to finding good moves is actually trying to find them! Good that you point it out!
When I was stuck in the 1200-1500 rating range I made this huge mistake that was holding me back, when I look back on it now I understand why, but I've been noticing that other 1200-1500s have been struggling with it too and I know the pain of being stuck at that rating range. The tip is STOP BEING LAZY. The main way that I was lazy was not calculating correctly, I would see a "good move" (something barely playable that I found in 5 seconds) and play it without a second thought, the only thing keeping me alive was my intuition. Some common examples that I've seen are people trading an excellent piece such as a knight outpost for a bad bishop that is blocked by pawns, people do this because they are too lazy and don't want to calculate for themself and their opponent's responses, there are other ways you can be lazy: such as not wanting to study or start studying (this will hold you back at every level), and even with things like game review (how do you expect to improve if you aren't directly addressing your problems). This is the most important tip to improve, and I hope it helps you.