Unpair watch when moving to new phone

i am migrating to a new iPhone (iPhone 8 to iPhone 11 pro max). I am trying to find a checklist that is more than just “back it up and restore”. What are the other things to do, and when do I need to do them? For example, when should I sign out of the iCloud? When should I unpair my Apple Watch? When do I reconnect to both. What do I need to do to complete these tasks? Any other things I haven’t considered?

thanks in advance!

tbdbitl.