@NOORITHAYA Hello, check in the settings of the Whatsapp / Storage and data app, if you do not have the option Use less data for calls activated.
In phone settings/Applications, look for the Whatsapp app-in the options /Battery, have the setting in Optimized.
I have F62 I'm facing same problem.
WhatsApp video call Immediately frozen and WhatsApp is not responding pop-up. needed force stop for disconnect call.
i reinstall WhatsApp from Play Store but facing same problem again.
Instagram video call working fine.