Okay, you are talking about "Clip Studio," not "Clip Studio Paint."
Clip Studio is kind of the launcher/hub. Clip Studio Paint is the actual art software. Weirdly, I had no trouble getting Clip Studio (the hub) to work in Linux - the part that kept crashing was Clip Studio Paint (the art software). The problem with installing Clip Studio 4 and updating it is that you end up paying a lot more that way because you have to buy the license twice. The v.4 + v.5 upgrade is cheaper than buying v.4 + v.5 outright, but it's still considerably more expensive than just buying v.5.
I think the reason it's built in with Edge browser windows is because they only really expect Microsoft users to use it. On iOS, for instance, when you search for assets on the hub, it doesn't load the web pages in-app - it opens a browser (Safari in this case) separately and has you complete the operation through that (since everything in Clip Studio is mostly tied to your account and not your device).
