Did your brothers iPhone SE 2 was able to connect with WPA3?
ath10k-firmware-qca9984 CT firmware I was not able to connect a Apple Ipad Model A2602. I switched to ath10k-firmware-qca9984 v20230804-1 and the same. The Ipad was still not able to connect to my WIFI at all.
Then I disabled WPA2/WPA3 Mixed Mode and know it works.
See this post here too. spoiler: we blame apple for that: