Need help spotting whats wrong? Although I would prefer just figuring this out on my own I feel like I need a stronger or more knowledgeable player to help me out here. I keep seeing a lot of my losses are when I'm up in material, low on time and in the endgame. I just don't understand why this pattern keeps reoccurring. Although it may seem obvious that my endgame skills are the problem it just doesn't feel like that is all there is to it. Here I'll try post a couple of games as an example. I also can't seem to add annotation unfortunately which means it'll be harder to explain some of the silly errors I made. These loses always tend to be the most painful and cause me to sometimes even consider quitting all together.

I play as black in this game. Also note I was low on time in all these games (not saying as an excuse for losing)

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1. d4 Nf6 c4 e6 a3 c5 e3 d5 Nf3 Nc6 Nc3 Be7 dxc5 Bxc5 b4 Be7 Bb2 O-O Be2 dxc4 Bxc4 b6 O-O Bb7 Qe2 a5 Rfd1 Qb8 b5 Na7 Na4 Nc8 Be5 Qa7 Bc7 Bxf3 Qxf3 Qxc7 Qxa8 Qxc4 Rdc1 Qxa4 Rxc8 Qxb5 Rac1 g6 h3 Kg7 Rxf8 Bxf8 Rc7 Qb1+ Kh2 Bd6+ g3 Bxc7 Qb7 Bd6 Qc6 Bxa3 g4 b5 g5 Ne4 Kg2 Nxg5 Qc3+ f6 Qxa3 Qe4+ Kf1 Nxh3 Qe7+ Kh6 Qxf6 Qf5 Qh4+ Qh5 Qf6 e5 Qf8+ Kg5 Qe7+ Kf5 Qd7+ Ke4 Qc6+ Kf5 Qd7+ Kg5 Qe7+ Kg4 Qd7+ Qf5 Qd1+ Qf3 Qd7+ Kh5 Qxh7+ Kg5 Qe7+ Kh6 Qh4+ Qh5 Qe7 b4 Qf8+ Kg5 Qe7+ Kg4 Qd7+ Qf5 Qd1+


Lost on time, I'll show one more even though I've got way too many examples of games such as these haha.

Playing white this game

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1. e4 c6 Nf3 d5 Nc3 d4 Ne2 c5 c3 d3 Nf4 c4 Qa4+ Nc6 Qxc4 e5 Nxd3 f6 Nc5 Qd6 Nb3 Be6 Qd3 Qc7 Qc2 Bd6 d4 Bf7 Bb5 a6 16. Bxc6+ bxc6 17. Be3 Ne7 18. dxe5 fxe5 19. Nfd2 O-O Bc5 Rfd8 O-O-O a5 Bxd6 Rxd6 Nf3 Rxd1+ 24. Rxd1 h6 25. Kb1 Rd8 26. Rxd8+ Qxd8 27. Nxe5 Be8 28. Nd4 c5 29. Ndf3 a4 30. Nd3 Qc7 31. b3 a3 32. h3 Qa7 33. Nd2 Bh5 34. f3 Bf7 35. Nc4 Bxc4 36. bxc4 Nc6 37. Qd2 Na5 38. Ne5 Qb8+ 39. Kc1 Qxe5 40. Qd8+ Kh7 41. Qxa5 Qf4+ 42. Kc2 Qe3 43. Qxa3 Qf2+ 44. Kb3 Qe3 45. Qb2 Qd3 46. a4 Qd1+ 47. Ka3 Qd6 48. Qb5 Qe5 49. Kb3 Qd6 50. a5 Qd1+ 51. Ka3 Qa1+ 52. Kb3 Qb1+ 53. Ka4 Qa2#


some obvious mistakes here like one of the many was me trying to trade dark squared bishops when his one is absolutely terrible, I regretted that choice during the game immediately

Also just remembering that my nerves tend to play up sometimes or I get quite emotional during play which I'm confident effects the ability to focus or think clearly. Although I try to work on this problem sometimes it feels like it can't be helped and everything just becomes somewhat chaotic in my mind. Maybe its my ego or my strong desire to win or not lose that is causing this, I'm not entirely sure. Honestly all these games look to me like I shouldn't be playing this bad and its not showing my real skill but that is really only what I feel about it and in reality I did play those games and there is no excuse and I guess I have to take responsibility and I deserved to lose.
Here are my observations:


Both games are long. The average game lasts about 40 moves. No wonder you ran out of time!
I can see you know the principle that when you are ahead in material, trade down. However, both games involved your king being chased around by the queen. You are not trading the right pieces
You don't need to be up that much material to win a technical game


Advice:


Learn to play more efficient chess. I'm guessing it took you some time to figure out all the branches in the tactical analysis


I feel that you are trying to find the best move by calculation. I.e. that you are trying to see 5 moves ahead to see if you can win more material. What I believe you should do is aim to look 2 and a half moves ahead and base those moves on your evaluation. This is particularly useful in non-tactical situations.

For example, in your first game you win material and have to solidify. At move 31, you make life more complicated for yourself with 31...b5. Why not offer to trade queens with 31...Qe4, which needs almost no calculation? That move follows the principles and is in line with your evaluation of having to solidify and trade down.


When ahead in material, your first priority should be to trade queens. This is a big reduction in material and reduces the opponents counter attacking chances a great deal
Don't spend so much time gaining more material. Spend time either solidifying your position or reducing the opponent's counter chances