So, I’m aware of Syncthing for much of the media, which may help after getting things migrated, but I’m wondering if there may be something more like Clonezilla (or the like) for smartphones to more easily copy over apps & media in bulk.
I also know that the Play Store keeps track of installed apps and I can go through it to individually reinstall each one, but I imagine there must be a much better way.
For most user data, install rsync under termux and upload the relevant directories to a server or even to the new phone across your LAN. For apps, just reinstall the ones you actually use.
Browser bookmarks and passwords are kind of difficult unless you enroll a firefox account and I’m resisting that on principle. I don’t have a huge number of them so I’ve just kept the old phone around and have been recreating bookmarks and re-entering passwords as needed. If I really wanted to do it in bulk there are messy technical ways (basically run your own version of firefox.com on a server) that I haven’t pursued. Rooting the phone is another option.
The 2FA app on my old phone poses a more serious problem since there is no way to extract the data from it without rooting the phone (I might try that), and there aren’t TOTP apps on F-droid that I like at the moment. I think my first Android project might be adapting one of the existing f-droid ones to do the right things.