I think the first thing was Windows' fault (and also the fault of my dual boot setup, which i imagine most casual users won't be going for) - apparently "Fast Startup" means doing some hardware shenanigans that prevents Ubuntu from hooking into the motherboard's network adapter.

After disabling that, I had to install a specific version of the nvidia graphics driver (535) from a PPA to get all 4 of my monitors working. Before that, I couldn't configure display settings at all because my screens would flash for too long and prevent me from clicking the "Keep Settings" button. And before that, only one monitor worked and the other three were black screens that I could move the mouse to, but couldn't move applications to.

And finally I had to figure out how to set a "default" audio device because apparently this isn't a configurable thing (that I could find). I noticed I would have to manually set my audio device after every reboot - after enough reboots I found that there is a command to list audio devices by ID and to set the active output device by ID, so I added it to the list of startup commands. Honestly this one is the most perplexing because I would think setting a default audio device from a list of multiple would be some pretty basic functionality. I'm guessing that I probably just missed it, or gnome hides it.

After that is mostly gaming setup stuff. I would consider it to be common knowledge that most games aren't intended to be run on Linux, so I don't mind some difficulty there.

Slightly unrelated, I have learned that apt purging openssl is a huge no-no and am now reinstalling Ubuntu again entirely :)