Some other users have fix it by uninstalling KB5079491.
https://learn.microsoft.com/en-us/answers/questions/5845847/how-to-fix-white-screen-on-whatsapp-web-after-wind
Go to Settings / Windows Update / Update history and scroll down to Uninstall updates. Select that KB and uninstall it.
If that help then pause updates untill next Beta build is released.