How do I delete iOS 15.1 update I don’t like it how do I get 1.14 back

Update 15.1 is horrible which how it makes notifications look how you access the focuses and everything else it adds is really bad but I use a iPhone XR and i am wondering how to revert back before 1.15 and over to 1.14 and don’t say go to iPhone storage and delete it I tried that the delete button did not work so please help