While I don't enough about the problem domain and the app, "just don't use WhatsApp" is not necessarily helpful. The dev experience might be better, I dunno, but your product also needs users, and in my countries / communities, WhatsApp is the only thing they use, and meeting your users where they are is important.

Forcing your users to first install one more messaging app is going to cause people abandoning you immediately or slowly churn, which can make or break a product.