I found this Dual Extruder V3 Fan Duct and the description makes a lot of sense so I printed one for my TAZ 6.
After a bit of fiddling with the wiring harness, I was able to get enough slack in the stock fan wiring to use it without any cutting and soldering of the wires.
The original author used PLA but I used PETG because I had some. ABS would also work and might have a bit higher heat tolerance.
I haven’t had a lot of heat creep issues with my dual extruder but I believe this will help and I’ll report back when I have more time using this new fan duct.
I have a Noctua NF-A4x20 5V fan on the shelf which will be my next modification (mounted on this fan duct) if necessary.