Migrating my data to a new MIUI Android phone

I'm switching from a Xiaomi RedMi 3S phone (Android 6.0.1) to a MI 9 SE which I just got. None of the phones are rooted. I don't have a Google account, nor a "Xiaomi account" - but like any phone user, I have my contacts, history of phone calls, SMS messages, and conversation on various apps, and more generally a bunch of app data. I would like to transfer, or back-up-and-then-"restore", as much of this data as possible; with as little work as possible. Specifically, I'm hoping to be able to back up multiple things at once, or with one tool / method, rather than looking for app-specific solutions for each and every app. But - I don't want to involve Google or Xiaomi in any of this. What would you suggest? Note: * I'm perfectly willing to do command-line work or adapt a script if that helps. * If a reasonable solution requires rooting one or both of the phones, it's a viable answer, but please explain why that's necessary (as, obviously, I've refrained from doing that so far).