@emergingsoul - It seems you may have confused a passive output with an HT bypass, which is a unity gain circuit.
You state that you must turn up the volume all the way when using HT to get enough volume. This would be correct for a passive output, as at full volume the passive circuit will be passing through "everything" matching the input, i.e. unity gain at full volume.
For an active pre-amp stage, gain is added in the circuit. So unity volume may be at some point on the volume control that is only 1/2 or even 1/3 of full volume on the knob.
For a passive pre-amp, unity gain will only be achieved when the volume control is set to max volume. Any setting of the volume control knob, that is less than full volume, will only be outputting a portion of the input volume.
However! All is likely not lost. If you choose to use the passive output as an "HT bypass", you can simply set the volume control on the pre-amp to a pre-determined setting (like top dead center, or 5, whatever) and re-run the setup routine on your HT receiver. The setup routine will recognize the lower volume output of the channels connected through the pre-amp and the HT receiver setup will increase the relative volume of those channels to match the other channels in your multi-channel setup.
Really, it's easy-peasy, just one additional step you need to make when switching to HT. Just always set the volume control on the pre-amp to the same pre-determined setting you used when you ran the setup routine, and you should be good to go.
You could also use the tube gain output for your "HT bypass circuit" and it will likely more closely match the existing level of the other channels in your multi-channel setup. However, to get it "right", I would still recommend you choose a pre-determined setting, like top dead center, or "5?" This will get you the most accurate relative output of all channels. However, it will have the tubes active during play.
Otherwise, if you don't want to do this, send the Schitt back and get a pre-amp that does have HT Bypass.
Good luck. Hope it turns out well for you. I know it has been a journey and it is not working as you expected.
Sorry, if I've made any incorrect assumptions ok mistakes in my recommendations. I don't own the Schitt Freya, but I have done similar "combo" 2-channel stereo/HT systems using a 2-channel pre-amp/power amp to power the front L7R speakers.