I added in a EAP772, that's working great and is much faster on 6G. In conjunction with the EAP650 on a less frequented area system is stable now. Haven't noticed any drops since...

  @Arne17 

Was having the exact same issue with two EAP673, tp link acknowledged nothing. Just came here after another member pointed me to the thread to say that EXACTLY this is the solution to the problem. I am referring to enabling unicast conversions for all ssids. My networks are loaded with a number of chinese tuya crap and always thought that these were the culprits, but it looks like iphones are more likely the cause! Which is super weird for tp link to have no idea isnt it? For the record I also have PMF disabled, but if I disable the multicast to unicast and arp to unicast conversions on any ssid the apple devices connect to then after a few hours I get the 2.4 ghz band dying. Apparently increasing the 2.4ghz data rate control also help, but I have no actual confirmation about this. It is also unclear whether both or just one of the two conversion types are needed.

In any case, my saga continues because having multicast to unicast and arp to unicast conversions enabled leads to my iphone losing internet connectivity every now and then for a good 20-30 seconds or until I toggle wifi off and on, especially after moving around to different APs. I believe this has to do with ARP timeouts, potentially because of the conversions, and I would be very interested to know if anyone else had similar issues.