- Contacts are straightforward, just export/import on their web platforms.

- Calendar is tricker; I ended up linking my old one to not miss existing events and just create new events in the new calendar.

Everything else, like photos, mails and 3rd-party apps have not been an issue for me because they connect to the same clouds/services as before.

Btw, since you can do most migrations from a browser, you may just try it without buying a phone first.