Ideally, you should've deleted your WhatsApp account when Facebook bought it.
But it's not too late to wean yourself off of it and get rid of your account (though you have given more information to Facebook through WhatsApp all this while).
YMMV, but here are some suggestions. Turn off notifications and the message count badge completely. Then avoid opening the app. Do these for a few days until you realize that you're not missing much and are probably less stressed and happier than before. Get others to use Wire (I won't recommend Signal because it sucks and has a bad user experience even in 2019, and has only its protocol's fame going for it).
I don’t understand on what basis you made that comment and what you intended to convey. There certainly is a “WhatsApp account” and has been for several years.
WhatsApp calls every number as an “account”. I deleted my account when WhatsApp was bought by Facebook. Here are the links to WhatsApp’s own FAQ to delete one’s account on iOS [1] and Android. [2]
But it's not too late to wean yourself off of it and get rid of your account (though you have given more information to Facebook through WhatsApp all this while).
YMMV, but here are some suggestions. Turn off notifications and the message count badge completely. Then avoid opening the app. Do these for a few days until you realize that you're not missing much and are probably less stressed and happier than before. Get others to use Wire (I won't recommend Signal because it sucks and has a bad user experience even in 2019, and has only its protocol's fame going for it).