How to get away from owning a smartphone

Hey everyone, I was entertaining the thought of going away from owning a smart phone.

I already have a modded ipod classic that I use as my main music player.

I also know how to use a paper map.

I also have the Microsoft authentication app for work (I could just use my phone on wifi mode for this)

The last issue I have is WhatsApp where I communicate with friends and family around the world.

Is there a way to use WhatsApp on a non-smart phone? Or should I just buy a pixel and install a secure rom?