DOUBTS on my BEST GAME

I am white, he is black. 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 Nbd7 7. O-O e5 8. Re1 Re8 9. Bf1 h6 10. d5 Nh7 11. Rb1 f5 12. Nd2 f4 13. b4 g5 14. Nb3 Bf8 15. Be2 Ndf6 16. c5 g4 17. cxd6 cxd6 18. a3 Ng5 19. Bf1 Re7 20. Qd3 Rg7 21. Kh1 Qe8 22. Nd2 g3 23. fxg3 fxg3 24. Qxg3 Nh3 25. Qf3 Qg6 26. Nc4 Bd7 27. Bd3 Ng5 28. Bxg5 Qxg5 29. Ne3 Re8 30. Ne2 Be7 31. Rbd1 Rf8 32. Nf5 Ng4 33. Neg3 h5 34. Kg1 h4 Move number 14: why a4 is best instead of nb3. Move number 15: why a4 is best instead of be2. ( same question) Move number 26: why be7 is best instead of bd7 (both look same) Move number 29: why ng4 is best instead of re8. when I recapture with my knight, he recapture with his bishop and develop it. but if I play move like h3 the engine says he should capture my knight. (he wasted 2 moves by moving knight. and also I can recapture with my rook and improve my rook's position) Move number 30: why bb5 is best instead of ne2 Move number 33: why bxf5 is best instead of h5 "Help Me Understand — It’ll Sharpen Your Skills Too!". Thank you in advance

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