Hrm, some very odd results. The v4 and v5 versions of the vendors plugin should definitely work in the editor with Godot 4.7 on Linux... (I built my project with v5 and 4.7 on Linux!) It does sound like there could have been a bug introduced in Godot 4.6 or 4.7 that broke things.
I wish I had access to an original Pico 4, but I've only got the Pico 4 Ultra, and, unfortunately, Pico headsets can't easily be purchased in my country :-(