pretending that you need to use WhatsApp in 2023 is indeed a choice
It's not as easy as you make it sound. Between 2015 and 2022, Whatsapp's marketshare has increased a lot in Germany. So it might've been comparatively easy to drop it 8 years ago. It's not anymore.
Maybe I'd be able to convince a lot of my friends to install another app just for me. But it would be hard to do and involve a lot of arguing on my end. I'm not a missionary and I choose to spend my lifetime for other, more important things.