2.4 GHz no internet after a few hours, but 5 ghz is fine, MT7621 driver issue?

I really feel like this is a problem with the MT7621 driver.
There is the post about 5Ghz problem here OpenWrt on MT7621/MT7615N devices with 5GHz problems
and this other post about throughput problems 2 Gbps WAN/LAN NAT Routing on ramips MT7621 devices
I may have mis-linked to either of them in the past.