Thank you :D And yeah, I think it was itch's forum software that did you wrong. There was definitely an <img> in the post, it just didn't point to anything for some reason.
I'm still doing a little bit more reading on possible fixes for tablet issues (in general, when they don't seem to be getting along with specific programs) but it might be a good idea to go into your Wacom Center and set up a profile for Decker so you can tweak how your tablet interacts with it specifically.
I have a Huion so I'm not completely sure what's possible, but I'm thinking of things like turning off Windows Ink for Decker's profile so your computer will switch to the Wintab API instead. But there may be other options in there that could be helpful for bridging the gap like turning off pen pressure. (Decker doesn't currently support pen pressure, so you wouldn't be losing anything. The handful of variable-width brushes we have in the supplemental "all about brushes" deck and in wigglypaint use other methods.)