My uneducated guess is that it would run inside the prefix but would have troubles with basic Windows dependencies not availiable/running, prefix's folder structure being cut down to the most basic components and barebones, and that nothing actually runs like in Windows but is rather translated from Linux commands to Windows one and back? Meaning there's no processes or services like in a VM, no way to run cmd or powershell scripts, nothing to steal without leaving containment? Am I wrong somewhere?

I recall there was a wave of dread about Proton leaving host system easily accessible and not implementing any security measures as they are out of scope, but if we assume it's a virus targeting Windows, I'm half sure it would have troubles doing anything the usual way.

https://www.youtube.com/watch?v=d3fSnHTJdR0