Archer C5 v1 - 2.4GHz WIFI works but keeps grinding to a halt with no activity

TP-Link Archer C5 v1
Qualcomm Atheros QCA9558 ver 1 rev 0
OpenWrt 19.07.5 r11257-5090152ae3 / LuCI openwrt-19.07 branch git-20.358.74878-e019fd2

I have both 2.4 and 5ghz networks available. The 5ghz seems solid but doesn't have a strong connection over the entire house.

I use a few devices on the 2.4 network but every day or two I need to go into the control panel and disable/enable the network as the traffic on it stops completely and I get "no internet" reported by the devices I am using.

The 2.4 used to be rock solid but the last week or so it's just suddenly been unrealiable.