Hard to know. Will the interface be specific to driver versions? Will it require an updated kernel driver for each userspace driver as it does now? I don’t know that we have the answers.

Worth noting that Nvidia only intends to open source the kernel driver. This is only half the driver, as a userspace blob will still be required, and that will remain closed and proprietary.

I’d start with checking logs with journalctl as a privileged user. If the device disappears, there should be logs about it. Maybe that will point the way.

It would be worth looking through your journal. There is usually some amount of logging even in the event of a hardware issue. See journalctl.

As others suggest, does sound related to sleep / suspend. If that is the case, you could have a problem like I did where my motherboard BIOS incorrectly reports usb capabilities which results in an immediate resume from sleep. That abrupt change causes the amdgpu driver to crash, and the system hangs soon after. My workaround is to disable features on the offending usb host controller.