Disclaimer: I’m a Firefox user.

Support for Opera wasn’t a completely separate effort, it just happens to work because, like you said, it’s Chromium based. If it wasn’t, it wouldn’t be supported either…

There are multiple steps in between for installations, but yeah the attack surface is quite large…

You’re the first I’ve heard doing this, how does the interior screen work with Graphene? Are there any optimizations to take advantage of it? Or limitations (split screen apps?)? Sorry if these are dumb questions

If EA Play is the only barrier to playing these games, you can definitely get them installed and try them out with Proton.