How does Fallout 76 decide to run like shit?

Sometimes it’s really smooth. Doesn’t matter what Linux is doing, it can be doing nothing, and the game runs like shit.

Does their server somehow make the game run like shit? If so, they should fix their server, or get better hardware. Or maybe it’s the USB ethernet adapter I use with Windows. I could make a bridge again, but I’m lazy. Somebody said the bridge caused stuttering.