Problem setting up Talkback.

You should try with the cue mix. “Mix” should work as well though.

You should hear the Performer at any time thru the VST Connect Monitor plugin residing after the Studio Monitor output. Pls. make sure this Monitor output is what you actually hear. To repeat: in the Devices menu/VST Connections (not to be confused with VST Connect), you should set your main Output ports (“Outputs” tab) to “no connection” and in the Studio tab, there should be your Monitor output which should be assigned your actual monitor (output) hardware ports, probably out 1+2 of your Apollo.
Then, you should always hear the Performer because the incoming signal from the Performer is routed directly to the VST Connect Monitor plugin which resides after the Control Room (Studio) Monitor output.
Then once more I am confused as you say again Talkback “works but only when I activate the monitor button on the performer track.” When talking about “Talkback” we are talking about the Performer hearing you (not vice versa), right? Then it makes no sense as the track Monitor button (which you shouldn’t use at all on Performer tracks) has nothing to do with what the Performer hears.
Once more the signal flow:

  • Studio Cue Mix (incl. click, Talkback etc as set up in Control Room mixer) → Performer
  • Performer → Studio VST Connect Monitor plug and also Performer Track input for recording.

Yes, that is how it works. It automatically replaces recorded stereo mix but also creates new tracks for single channels when they were record enabled individually, including all edits, drop ins etc.

It happens to me all the time too…every now and then I unsubscribe and immediately “re-” subscribe again.