I think I found the issue for my computer problems, and this time it might be the pen itself. The tip is considerably worn down, but it's been that way for a while. So, my main theory is that the pen's ability to form different lines based on pressure has been pretty much shot. which would explain why all the lines in SAI, despite being smooth (the lack of smoothness usually is the whole "tablet driver not found" deal which I know how to fix) don't have a lot of variance in size based on how hard I hold the pen down.

Now, the next issue is how the fuck to fix this, since this is hardware, which I am NOT good with. I either have to order new pen tips or a whole new pen, but I don't know how to make it work with the current tablet. And I honestly don't want to contact customer support because...wacom...but I might need to.