“To use Whatsapp as an example, consider a scenario when a user need to use this app (say for business), said user is not concerned by the content that is being transmitted there but IS concerned about having an untrusted app (ie: whatsapp) on her phone, especially considering that this app requires every possible permission on the device.”
There’s matrix.org out there with bridges for signal, whatsapp, discord and what not. IIRC the bridges still require an Android for registration once.
Also, they terminate the then-not-e2e-anymore encryption. However that should be fine if you don’t care about confidentiality.
Lazy people can even get it as a service for 5$/month or so.
Disclaimer: I haven’t tested it myself yet.
“A nice App-VM on qubes, running android with just that app will solve the problem nicely.”
That would be another interesting solution indeed.