Latest version I know is 8.4.0.2 from 2020-05-16 downloaded from here http://www.matrixrewriter.com/android/files/TitaniumBackup_latest.apk.

I use Titanium since Android 4 and had indeed some troubles (related to storage access rights) on Android 11. After solving those, Titanium ran fine like on older versions of Android. Did not yet try Titanium on newer versions than Android 11.

Thank you for the hint and link to Neo Backup, I will give it a try. (Ah, just saw it is an incarnation of OAndBackup, nice.)

I am not aware of any advantage, but my family and friends are using either Threema, Signal or Telegram. So I use all three of them.

My Android paid must haves are: Titanium Backup (for scheduled backups and quick recovery), Threema (Messenger) and airMusic (former AirAudio, stream from mobile to e.g. Sonos).