Having the same issue on note 20 on sprint/tmobile I got it Friday and worked fine did an update and not working talked with sprint they can't figure it out went on samsung for help he took controll of phone and turned on a few things. Got it to say delivered but would send a message every time for a "delivery report" every message i would send and if other person read it wouldn't say read. The chat feature is missing now too I have a few screen shots idk if they will help at all. First one is a message before problem says message type "chat" second is after update says "text message" third and forth pictures are what Samsung turned on and 5th and 5th are the message saying delivered but the delivery report showing up in notification. Hope someone can figure it out samsung guy didn't really know what to say just said they are updating and making things better for all users all the time and might of been a feature that was removed.