what i noticed about your gameplay is your patience, aside from you're a really great SG user while having great accuracy your patience always leads you to better positioning and precise spots where you can get the advantage to engage, hats off
I think to get your new record (and possibly a world record!) you have to recycle the players more. Like at 7:21 you could have left that guy to revive the x3 tags to get a shot at extra kills. Try leaving more of the final player alive to bring more back into the game and you'll get your 40+ again!