I tried to play with someone on other platform (I’m on ps and the other on switch) we’re both in the vc and for me it shows I’m the only one there and also when I speak it doesn’t show my icon at the top left like it always does when you speak. I checked and the switch player see two players in the vc but can’t hear me too…
Go to groups and make sure the headset icon is selected. That has worked for me. Also I’ve had to restart the game or console to get it to work
Make sure both you and your friends has enabled the cross play communication in settings.