The "not working" refers to the same issue as explained before (nothing has changed)
I started a few things to try there - I need to know what you tried, if you can turn off the 2 GHz radios, if both PCs are connected to 5, are both connections rock solid.
Another things to try when everything is connected to 5G:
Admin command prompt -> ipconfig /flushdns
In MP, connect to the IP and not the hostname only AFTER connecting to the 5G network and the IP is known, example:
Stardock Support Manager