Not a helpful comment.

As somone who has slowly moved away from big tech, one of my steps was to use unofficial clients (open source) and web wrappers. For others it's impossible to move fully off a platform for reasons like work, school and family. Ulimatums for these don't work for everyones situation.

Many people use open YT apps or proxies. Versions exist for Twitch. There are ways to access Spotify. Nitter is back (for now). Their used to be some FB wrappers (I think they exist but are pretty bugged at this stage). Why would OP expect any less of WhatsApp.

And to answer OP. The best I've heard is use a PC with a burner number and a web wrapper on mobile. It requires some sort of regular login on the PC.