OK, I found the solution, the offending registry entry in Proton has moved from:
HKEY_LOCAL_MACHINE/System/CurrentControlSet/Enum/
WINEXINPUT
to
WINEBUS
The same rules for editing them apply. I don't know who is responsible for this Steam/Proton or Elite Dangerous
But Proton is my main suspect, sorry...
proton 9.04x1 2026-04
Proton 9.04 on Ubuntu/Steam, Elite Dangerous
Seems like the uuid (or logic) for Joysticks is changed every few weeks. Actually I like Proton on Steam, it is stable and basically works with every game I tried so far. BUT the one exception are the Joysticks, getting highend Joysticks running is a journey. Details you can find here:
Add Joystick
About 2-4 weeks ago the uuid or the algorithm to create one was changed, it lost 4 digits. I fixed it in the registry, but today it changed back to the old uuid and I can not make it work again. I use 2 Joysticks, both allow me to use 80 buttons (each). It takes me 2 days to reconfigure it, if I can figure out how to make ED recognize them again. Can we please NOT toy around with these settings, or only if it is ABSOLUTE necessary...
)