It must've been a few days ago that my Wacom One tablet was working just fine, but now it's unresponsive. The tablet is sense by the OS (a new option appears in Settings when it's plugged in), but the stylus isn't doing anything. In fact, the stylus isn't getting detected by the OS at all, even when it's putting pressure on the tablet.
I think the kernel driver documentation would be the most likely solution if it's not working out of the box right now. But be mindful when installing kernel updates as you may have to rebuild these external drivers, or they may stop working. Or a kernel update may fix the issue and you won't need the external driver anymore.