You know what? That had not actually crossed my mind. It would not be the most convenient thing, but it’s certainly much, much easier than using a virtual machine. If running the Unreal Editor from Wine is known to work, then it’s a perfectly acceptable possibility. I actually assumed that, given how specific Unreal’s hardware demands were, it was a non-starter.
Proton is more complicated because it must be started from Steam, which ends up being yet an extra layer in practice. But if there is no other way, it’s also doable.