Earlier quoted context omitted.
Yes, but at least those don't have hardware lock-in.
WhatsApp absolutely has hardware lock-in. You need to be an Apple or Google customer to use it, and you need at least one Android or iOS phone.
Each one has varying models for replacing functionality of the Google Play Services, and IIRC the Aurora store [1] allows for installation of apps from Google Play without a Google account.
It's not a combination of steps that would be accessible to the average user, but I think it should be possible to use WhatsApp without being an Apple or Google customer (nominally a customer of Google hardware---Pixel phones---if using Graphene or Calyx, and ultimately a customer of Meta/Facebook for WhatsApp itself).