The latest version of WhatsApp Beta adds an option to the Privacy menu for authentication via a saved fingerprint. Unfortunately, this function is not actually live yet; however, it clearly indicates that the messaging app's developers will make it available in a future version. Reports suggest that it will be compatible with Android devices with version 6.0 or later and working fingerprint sensors.
https://www.notebookcheck.net/WhatsApp-is-working-on-fingerprint-authentication-for-Android-devices.393221.0.html
What a joke, Facebook and privacy. The best way to protect your privacy is not to share any personal data at first with companies like Facebook. I don't use any of their apps on my phone. I am using /e/ on my Galaxy S9 instead of Google Android. It is Android based mobile OS designed with privacy in mind. Does not send any private data like contacts, emails or location to Google. Instead of Google apps it uses open source android apps. So far it works great. You can check it at e.foundation