This is why I mostly go with “other” products.

Used to have a wacom intuos pro in the pass, had this happened with pen detection; A few things can come to mind;

On the software side: It might be Driver issues with the tablet (usually uninstalling the drivers manually, restarting the pc, then and reinstalling the drivers might fix it);
Windows ink funking up the drivers (If I recall Wacom has an option to use windows ink by default, perhaps turning it off and rechecking might provide insight if the issue persist).
[bit far off base on the actual issue but still worth looking at] Could also be a general stutter on the pc causing the driver to struggle a bit (things like high RAM load, high CPU load, or high tempts contributing to some weird behavior)
this is as far as software ideas go.

Hardware-wise, if you have a different pc, does the tablet continue doing that? if so maybe there is some false contact going on in the usb cable.

hope ya manage to find the source of the issue tho! >3< always irritating when these issues arise.

hadn't really considered it being the usb cable; could be
it's definitely not the pc stuttering, i got something that's considerably future-proofed now
i did try kinda toggling windows ink here and there but it never made a difference tbh

I try to have the pc set to windows gestures; wacom gestures are -far- too sensitive; sliding the screen makes it just kinda keep gliding all over and rotating while doing other actions at the same time, etc

I have not tried reinstalling the driver - i literally installed it for the first time last night - but i mean, i guess its something :/

I have both an old intuos and more current one. For the older one I realized a lot of the drivers stopped being updated for certain models and can be a bit clunky with 11. Do you use OpenTabletDriver for your drivers? It helped with some of my pen detection issues for my older Pro

Few things that come to mind,
As said by a few, drivers, make sure its the vendor one for windows 11 if possible.
Make sure any of the connections are secure to USB or GPU.
Make sure power saving is not set in the USB settings to make sure its not "assuming its not in use" and power dropping it
If the drivers for it are set to 10, it maybe see if there is any compatibility settings for things? moving to new OS can def cause unknowns from prev state

The only thing I can think of is trying out the compatibility trouble shooter in settings. Not sure if it works with hardware though.

In addition to the advice so far, I'd look for something to help scrub a lot of the W11 bloatware, as it can impact performance noticeably as well as just being annoying - the one I used is literally just called Win11Debloat, though I'm sure there's other out there now