All I did was post some results, no intention to bash.

I actually PAID to get these printed for my first printer since I had no way to print them myself (had to get all the gantry parts printed). I thought the design looked good. Once I model them into my carriage, and after they were already ordered, I saw a tutorial on how to do a CFD simulation. Due to issues with the model and being new to modeling and using Fusion 360, I took over 8 hours of my time getting better at Fusion 360 and learning SimScale just so I could do this simulation.
https://www.youtube.com/watch?v=Wun9EuVTV0w

I thought I'd share it since it was half my weekend working on this and it appeared to be a popular model with lots of uses, and on version 5.5, so I presumed it worked really well, but now we know. I also spent about 2 hours looking at the public projects simscale has hosed:
https://www.simscale.com/projects/#viewMode=thumbView&sortBy=project_popular&search=fan%20duct

To get an idea of how fluids/air flows and how to get it directional. Things I presumed were likely done on a duct that had gone through many iterations.

So, now you have the resources to make your v6 functional. Isn't it better to know your design doesn't work, at all, so you can improve it? You're welcome.