If you found the latest version of Titanium  Backup (now almost one year old with no recent updates…) cannot restore your apps data anymore on Android 10, this solution was found in the comments on the play store, by Stranger Stunts, published on 9/12/20.

Turn off “Verify apps over USB” in Developer Options, then turn off “Play protect” in the Play Store.

I didn’t test it properly but I remember last time I had such a problem I found a similar solution in the same fortuitous way, and it worked, but I didn’t have the idea to save it somewhere.

So I’m saving it on my blog for future reference.