With Titanium Backup unmaintained, Neo Backup [1] works pretty well. It has some potential issues with restoring wifi/bluetooth/sms as those were still experimental, last I used it. But sms at least worked. I'd suggest a 2nd backup app of those, just in case.

[1] https://github.com/NeoApplications/Neo-Backup

LineageOS includes Seedvault for backup and restore. It's not 100% reliably across devices apparently, but should typically work: https://github.com/seedvault-app/seedvault/discussions/331#d...

This requires both phones to use Seedvault though, so it's not an option when moving from the stock OS to LineageOS.

They're seamless. Any phone that allows you true `root` can do nandroid style backups which work very similar to how iOS does backups.