So it turns out the OBS Studio build available in the Ubuntu/Pop!_OS repositories doesn't support anything other than X264. This sucks for people who don't have crazy good CPUs like me.
However life shouldn't be that hard when it comes to live encoding h264 video, since OBS supports the ASIC encoder built into my nvidia GPU, yet the option is not available?
Turns out, you need an ffmpeg build specifically with NVENC support. There are tutorials online that show you how to do this, but my goal of using desktop linux is to not have to be a l33t h4x0r just to get things to work.
Thankfully, getting OBS with nvenc (and supposedly Intel vaapi) doesn't involve having to follow tutorials on how to compile something. Instead, this is from the power of containerization: Canonical's snapd.
On Pop!_OS, be sure to run
sudo apt install snapd.
Also, feel free to remove OBS which you may have installed from the repos with
sudo apt remove --purge obs-studio.
snap install obs-studio. Vioila! You've got a fully nvenc supported build of OBS! Congrats.
Just one note, if you go to the snapcraft page here regarding this package, appearently there are a couple commands you should be aware of for getting cameras or removable storage to be accessable to OBS.
sudo snap connect obs-studio:removable-media
sudo snap connect obs-studio:camera
The snapcraft page also mentions some workarounds if you run into known bugs at the time of writing this blog post which might be worth paying attention to if you notice weird behaviour.