> I'd love to just go over to Signal fully but then I couldn't talk to family, friends, and probably couldn't even book a haircut or pay my taxes (my accountant messages me on WhatsApp)
Comments like these make me think it's probably more a problem of inertia. Of course they can still talk to family (visit/call/email/sms/fax/mail,...), and of course they can still do their taxes, they might just have to get a different accountant that does business outside of WhatsApp. This all would take more energy than living in this beautifully convenient platform that Meta set up for them.
In the case of "business requirements", push back on businesses. You are actually the customer.
I get it though. The best might be a compromise where you try to limit the contacts on whatsapp to only those you have no choice.