The are ways to remove preinstalled apps like temporary root or editing webapp.json ; but, generally the people who buy this phone want to have access to whatsapp and facebook, that’s the entire point.

You should get a dumb phone if you don’t want pre-installed apps.

Yes, some softwares like wa and fb are preinstalled. Some of them you can remove it, some others I did not try, but it's enough not to login to avoid to use it and not to be tracked.