Slight frame-challenge here: I'm not sure you *want* OBS on a Pi 4. If you're going to stream or record, you definitely don't! I tried that myself, and it was a spectacular face-plant!
The preview kept up okay, and so it might have worked as a live display and nothing else, but the Pi 4 can't do anything that requires encoding. For that, the Pi 5 probably works, according to that thread, but I haven't actually tried it myself.
