There’s a flatpak in the Software app. I don’t know if it works or not.
Unfortunately, WhatsApp has become the default mode of communication in many parts of the world, even to the exclusion of mobile network calls, SMS, and MMS. From what I understand, lots of people, whole communities, and even businesses buy data-only mobile plans and then use WhatsApp for all calling and messaging, in order to save on costs. That has been going on since WhatsApp first appeared on the scene.
When the app was eventually bought by Facebook, it should have been a huge red flag to all users, but apparently didn’t cause a massive shift to alternative apps, because WhatsApp had become so entrenched.
Then again, billions of people still use Facebook, too, despite the privacy abuse.