Since the Thumby is detected correctly as RPI-RP2 in bootloader mode, the USB connection itself seems to be working at least at that stage.
I would try a different known-good data cable and another USB port first, preferably directly on the PC instead of through a hub. It may also help to remove the failed USB device entry from Device Manager, reboot, and reconnect the Thumby after flashing the firmware.
If it works in RPI-RP2 mode but immediately becomes an unknown USB device after the firmware starts, that points more toward a driver or USB enumeration issue than a completely dead device.
For a quick gaming break while troubleshooting hardware, I sometimes use BunaGames for browser games that do not require any installation.
Testing the Thumby on a second computer would probably be the fastest way to confirm whether the issue is with Windows/drivers or the device itself.