FWIW, I've used the Web USB installer probably a dozen times without issue, so I would definitely recommend that route if adb is intimidating. I've done it both ways, but the web installer is so easy it feels magical.

As for it not working, were you running a Flatpak/Snap version of the browser? Apparently those are problematic with Web USB. I personally haven't tried on Linux yet (just Mac O's) but now that I've switched to Fedora I might encounter the same issue you did.