39 Rxg7+.  And White should try to win that endgame with 44 Ne5+ (since after 44... Kh5 45 Kg3 Black's king is snookered).

Yeah in analysis I found Rxg7+ super quick but at the time I was in super time trouble with only a ten second increment so I had to spam moves to build up time. I was at 1 minute in the final position and I did consider playing for the win but I couldn't see how to free my king up from g3.

I've been trying some training where I just do easy tactics but with only seconds on the clock. I think it's more psychological though as I'm quite a nervous, skittish player. Thank you for the input btw.