Well, I lost my patience after a lot of research, went to soft reset, it works now, but the sensor fusion device is gone..
Edit : it didn’t work in the end, the rotation is gone again, and like the first time, it looks like Windows doesn’t display any options related to rotation, this is puzzling me. I think it’s pretty sure to say it’s not driver-related, it just happens after a few reboots when setting things up.
It’s was the Destroy Windows 10 Spying that disabled a sensor-related function in Windows, luckily it allows to fix screen rotation in its options, so after a reboot everything is working as a charm. For those using alternative solutions such as O&O ShutUp10 this appears as an option that can be disabled too, so be careful !