I currently have 3 of these and one outdoor mesh device for my shop. i am planning on connecting it to the wired network but thats not part of my issue.

I have noticed that my devices loose there connection. 

i have two LG oled tv's which when you turn them on one takes about 30 seconds to get its internet access from the network. the other can take minutes to get online. this never occured on my old network which was a single linksys router. devices that rely on the internet to get notifications will not get them sometimes until the device is woken. tablets etc. 
 

anyone have any ideas on what could be causing this issue with this network its really annoying and if i cant resolve will require me to switch to another device and i have invested quite a bit of money in these + the outdoor mesh device