That’s actually not bad, if this is the only thing (hold on, after looking into a bit it could be a show stopper still). An idea is, if its not too many files, would be to save them from this application in a more universal usable format and not use it anymore. But that comes with ton compatibility issues on itself, so who knows.
It seems like WINE (the tool that is used as main part of Proton in Steam) can run Clip Studio Paint, but not great (Silver rating): appdb.winehq.org/objectManager.php?sClass=applica… And then the question is if it will even work well with Wacom devices this way. Also I’m a bit worried if it will work well in a VM too.