I had this problem some years ago. Eventually I just told everyone I would be uninstalling whatsapp on date XX/YY, which I then did. Some people installed signal and stayed in touch, others didn't. Life didn't change much.
Now I'd like to move to my own matrix server but I think appx 0.0% of my social group would follow me down that rabbit hole. :-(
More extreme, a friend of mine one day eliminated his cellphone entirely but kept Skype on his laptop. So now it's email or nothing with him and sadly it's been nothing for some time now.
I left whatsapp long ago when it was bought by meta, due to my privacy beliefs. I quit facebook in 2007 when i caught negative behaviour patterns. Im staunchly anti social media, however it would be dishonest not to note that it is lonely, organising anything is tedious, you have no access to the used goods marketplace (fees on sales platforms are too high). I dont really know if privacy is worth it. But tbh the thought of going back makes my skin crawl.
More extreme, a friend of mine one day eliminated his cellphone entirely but kept Skype on his laptop. So now it's email or nothing with him and sadly it's been nothing for some time now.