The actual original leather case from Samsung for S22 ultra is the one shown in attached picture which is different from what you have. Probably the case that you have might have some material which might be hindering with the antenna of the phone since what I have understood from your message is that without the case things are pretty okay. Try switching to the original case and hopefully your issue will get fixed. BTW the original leather case only come in black, white and burgundy colours. Thanks and warm regards 
