If you're stuck with a low profile graphics card at 2GB or more Fallout 4 may still run fine at 1280x720 medium. I just tested it with an old Nvidia GT 1030 2GB I had laying around, just because. My regular GPU is an Nvidia RTX 3050 8GB. Here's a short video showing the GT 1030 2GB in action. Bare in mind fraps stutters the footage a bit. https://rumble.com/v3akvo6-fallout-4-gt-1030-2gb-test.html

OBS might have less overhead. Might record better.