Wifi getting throttled until restart

I am running OpenWRT 22.03.2 on a Linksys WRT1900AC v2 as main router
And OpenWrt SNAPSHOT r26436-7514d9bb6f / LuCI Master 24.135.65178~2bb1e06 on a TP-Link EAP225 v4 as Access Point

My issue is that after a while (not sure exactly how long but less than a day) the Wifi gets throttled to ~1Mbps per client, if I restart the AP the speed is restored to normal.

This feels like some kind of QoS setting but I can't figure out what it is

Both devices are supported by ofgicial stable release 23.05.4, will you be able to repeat (rather generic) setup using that or you need some helping hand/ extra guidance?

My original issue randomly solved itself a few days after my post, not sure what the cause was.

I would like to upgrade but I am not entirely sure what the correct way is, there are builds per model Right?

Draft on paper and sysupgrade with resets.