Still trying to understand routing possibilities

Routing has been a bit of a moving target for me. For years I outsourced everything to Carla over many MIDI and audio buses.

Then I switched to pulling the plugins back into Qtractor and only using Carla as a bridge by way of placeholder buses to serve as over-glorified bridges.

More recently, I eliminated Carla all together by leaning into Carl Irwin's most excellent routing pattern making heavy use of Inserts. So far, this has been the best pattern as everything is quite clear but it does have some drawbacks in terms of creating inserts and chasing after then (output port assignments) each time a new track is added. Some people here know (and probably use) this workflow and would recognize it by the steps involving renaming the native Master bus to IGNORE and creating a new Master bus sitting at the end of the chain.... yada yada.....

Which brings us to today.... Rui has done a bunch of work recently which essentially decouples the baked in Master and there's been much discussion as of late on how to tap into all the routing possibilities by way of Aux Sends. The thing about these Aux Sends of course, is that they are (still) pre-fader which means the signal is forked before it has a chance to be influenced by a strip's volume slider, or pan.

Essentially, the usable area of a bus strip with an Aux Send is reduced to this:

OK, that's fine. We understand an Aux Send makes a copy of the signal and ships it pre-fader. So we want to come up with another means to impact the audio signal with a bus' gain and/or pan sliders. Here, I've added a 2nd track called Synth 2 which has its Audio assignment assigned to the Synth 2 bus. That bus is sending output to a Audio Insert placed in the first slot of the MixDown bus. The important thing here is that the Synth 2 bus is panned hard. We can see only 1 channel is being output.

To my surprise and dismay, soloing this track produces signal straight down the middle.

So I'm either entirely dumb (possible) or something is not happening that should? It just seems like it shouldn't be this difficult to route and manage signal across a mixer. I'll attach the .qtz if anyone is interested in poking at it.

One thing I should probably also mention is I've been very consistent about NOT trying to mix (volume and/or pan) using the Track strips. The reason for this is I work nearly 100% with MIDI and therefore, really don't benefit from those sliders in the way that people who work primarily with audio do.

Thanks in advance.