Are you writing that more than one device can't do WiFi to either router?
I'm not there to see your setup but I did make a call and the owner thought the antennas were bad looking and optional on the router.
I lost my network signal a few days ago. I cannot access wifi but can connect through ethernet cable with no issues. I tried to see if there was a firmware update for my Linkys but it was not available. I got a new router Belkin and it does the same thing. I am not able to coneect to wifi after set up but have no problem to do it through Ethernet cable.