I haven't tested Opera GX until now (since I don't use it) with a fresh install of it. No issues on my end.
It's a known thing in online forumboards that Ren'Py can have problems running on certain hardware, graphical cards, drivers, and/or renderer settings (it's difficult to find thorough lists of that though).
(At first before I could see your report, I wasn't sure if Ren'Py web builds are supported on smartphones, but I've tested that it runs on my Android phone as well.)