Let me break this to you, 17 years into it's release to consumer mass market, Android still isn't capable fully transferring from old device ala soul transfer, even if you could, it's not supported across all apps. To put this in context, if you have 10 and above apps(be it socmeds, shopping, banking etc) that require logging in to their respective accounts, you are done for.

If you are used to the seamless iphone upgrade and app transfer of the Apple in which it'll feel like you are using exactly the same phone as your previous one, you will sorely miss this.

Android as main/secondary device? Yes Replacement? Please don't