Hello.
Yes, I've been using WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1 on WAX620+WAX630. Low latency, stable and I do not have any errors/issues as before.
I don't use FT or anything on my setup. I figured out that the simple wpad-basic-mbedtls was enough too.
In terms for latency, I'm going to do some crusader tests between the WLAN.HK versions like I did earlier with Flent. 2.6 = 50ms, 2.7 = 55ms, 2.9 = 100ms.
I've been also testing the AQL patch for IPQ807x. But crashes as soon as a client connect to the wifi. 
https://patchwork.kernel.org/project/linux-wireless/patch/20230501130725.7171-1-quic_tamizhr@quicinc.com/