Is there a way to be listening to music in spotify so i can hear it but OBS doesn't pick it up?

So i've been trying to get back to speedruning this game but i realised that there is a bit of lag that makes all runs slower. I tried older and newer versions and different launchers but nothing seems to work.

I made also this video comparing a new run i made and my warpless pb, it loses time to lag (and beeing bad) both in movement and in the marathon

Video

If anyone could help i would appreciate it as i can't speedrun the game this way.