I moved to a new city & want to change my area code & ph#. How do I do this?

I'm really worried about losing data such as my text msg history/groups, apps, etc.  When I change ph#s, will my phone look the same and contain all the same information/apps/contacts/photos, etc?  (I have an iPhone XR if that makes a difference).

Is there any reason I should NOT do this except for the hassle of letting all of my accounts/contacts know my new ph#?

Anything I should defenitely do on my phone or with my phone data before changing my ph#?

Does anyone know what callers will hear if they call my old # after it's changed?

Thanks for any assistance on this!!