Since applying the solution proposed by 0xwojak I’ve had no more problems using the laptop.
However, I do experience a systematic freeze (100%) when I want to shut down the computer via the graphical interface (menu → shut down → reconfirm shutdown and then a complete freeze). I’m using KDE with Wayland.
I’ve also had rare freezes on session startup.
In short, no, the problem hasn’t been solved, even with the advice given above.
The open driver version 550.90.07 doesn’t fix the standby problem either.
Pathetic, very little progress, no reaction from nvidia for so long.