Galaxy Tab S7+ WiFi only. Locked in demo mode. Help please


Jul 22, 2020
Hi recently bought old tab s7+ but it's locked in demo mode, can't change it in settings, anyone know what I can do to restore it. Also will not update to latest Android version. Thanks for any replies.
Does Samsung Touchwiz allow you to control any changes?
touchwiz? thats very old. samsung now uses OneUI. and what do you mean by "control any changes"?

both touchwiz and OneUI are just samsung's launcher that they put on top of the android os to make it look and fell different from other manufacturers. i dislike OneUI so i use the Nova launcher that you can get in the play store.