I restarted SteamVR out of boredom. i got it in a state where despite still got the error 307 popup, it was displaying the VR view on my main monitor. Previously, when it was properly borked, the only tab in steamvr settings was the "startup/shutdown" tab, but now the other tabs were visible. I remembered that one of the things I changed earlier was the framerate. I set it to 120 (from 144) and now steamvr runs fine.
Nothing extracted yet.
Describe the bug

These two windows appear. steamvr does not work. Nothing is visible inside the headset
To Reproduce
Expected behavior
SteamVR works.
System Information (please complete the following information):
Mesa 22.1.6Additional context
It worked for a bit. and then I changed something. no idea what I changed. maybe it was re-ordering my cables? but I think i've tried all the variations.
another version of this issue from years ago said to check
dmesg:Note: Commenters who are also experiencing this issue are encouraged to include the "System Information" section in their replies.