I've been having this issue since the Witch Queen drop as well on a modest but older PC with an RTX 2070 Super. Used to have smooth 80-144fps across different game modes but stutters got worse as I kept loading into different areas. I read that rolling back drivers to the previous version on Nvidia cards would solve the issue so I did it last night and it seemed to work well even after 90-120 minutes of crucible gameplay. You might not get the performance you want on more recent games the latest drivers were supposed to support though; I booted up Elden Ring afterward to find that gameplay suffers greatly on running on the older drivers.

There is indeed a memory leak, I've got it twice now. (2 different sessions but same results) Just tonight pc total was using 80% (typically pc no gaming etc idle is between 18%-20% so we could say it was using 60% of my 16gb ram commit was 21gb physical+virtual (which is page file) I have 8gb vram noticed that was full to so im guessing its starting in vram once thats pack nice and full she starts eating the system ram. probably took about 3-4hrs to achieve an unplayable state. At which point i have to restart game. A google search has turned up countless reports all over the place reddit etc within past 15 days. I'm sure bungie knows by now, lets pray for a fast hot fix anytime soon.