instead of Nc3 i think in the beggining of the game you should have moved your other knight so you could capture the pawn.
One of my games
4. Be2 is not good or bad, it's pasive Bb5 is much more aggresive move
6. d3 , blocks ur bishop that is defensive and stops e4 , ok move for me Nxd5 is also good
7. it takes away long castling but u didnt plan to castle long any way, it's better to say it's opening attack vs black queen side cos with ur peon on d3 , locked bishop and queen attack on queen side looks as the best solution
9. Bg5 attacks queen without any idea, make a plan, like let's attack one side, let's push on centar with peons etc
13. Bd2 after this move u can see that black will attack ur king side soon and u didnt prepare ur conter attack on queen side or something else so u have to defend
15. Nd2 let's ur oponent to exchange and remove some defenders on the side on which he will attack
17. exd4 Ur opponent made a mistake, made a bad exchange and now u are back in game and then u run in fear from him with queen exchange, u were better , he had too advanced peons and u shuld not exchange queens
21. c3 u are undoubling the peons but ur peons were good, holding center, weak peon on c2 was far from danger and u just made ur d3 peon weak and target for attack
Lucky win :)
U are tring to simplify to much and pushing to end game without advantige
hope it helps, just some of my views
6. d3 is not a good move, but neither is Nxd5, bringing the Black queen to powerful central square. The best move is 6. Bb5, which is the equal line 1. e4 e5 2. Nf3 Nc6 3. Nc3 Nf6 4. d4 exd4 5. Nxd4 Bb4 with reversed colors.
On move 9, instead of Bg5, you should've used a standard rearranging plan with Re1, g3, and Bf1-g2.
14...Bg4 is a bad move from your opponent. Instead of exchanging a good bishop for a bad one, Black should be looking to play ...e4 and then pawn storm on the kingside.
50...h5 instead of ...Rh2+ mates.
Like to have comments from memebers.Thanks!!