Did not help. I will not be re-enabling the 802.11r and i will be trying out the DTIM interval thing although I only have one apple device on my network (iPad) and it's hardly ever used. #TeamAndroid
I'm going to set the DTIM to 6 on the 2.4 Ghz and 3 on the 5 Ghz and the GTK to 86400 as suggested by this post
This other thing looks really interesting to speed up wired connections between devices on the same network, but I wasn't seeing anyone solving WiFi problems. So I'll try that next I guess.
I also need to try turning my EA7300 into a dumb AP and let the old 6220 do the routing job to see if the problem persists in either.