Hey @Ocebir ,
Can I ask if this is affecting any other app at all? Have you checked if there are any pending updates for this app on the Google Play Store> Menu> Manage apps> Search for the app> Update?
I can see that there are some reports stating that there are some issues with the Whatsapp app on the new software. Have you tried to report this to them using the details available in the Google Play Store> Search for this app> Scroll until you see the Developers' information?
Try to send the edited video to fb messenger, it has sound. Save it and then send to whatsapp. Now it has sound. I don't know why I have to do this but that's d only way I can so for now.
I can also confirm this to be an issue.
S20FE on android 12.. Screencap edited to crop > shared via whatsapp -> No sound
Sent as a file to iOS and returned via whatsapp - > has sound