Yes, I think I mean the ipq-wifi firmware. It is the firmware located at /lib/firmware/IPQ8074/
I haven't applied any rigour to my playing so far, it is all very rough. I need to understand the subsystem better so I can define the problem and work out how to get meaningful logs/debug information. I'll keep digging in other threads until I understand enough to ask sensible questions.
I've been using the new 6.12 (formerly testing) kernel for the last two days on a EAP620 HD v1. It's running well, I haven't noticed any disconnections or instability and performance is comparable to stock firmware.