I’ve been using the Opal app since February and really enjoy it — especially the Deep Focus Sessions. I love how it prevents deleting the app or making changes during use. That said, I recently found a workaround that defeats the purpose: by going to Settings > Screen Time > Apps with Screen Time Access, I can just disable Opal.
I’m not sure if iOS allows it, but it would be helpful if access to Settings could be blocked during Deep Focus Sessions. Right now, it seems there’s no way to do that.