Router is visibly working, but my devices refuse to connect.

I want to say first that I am a complete noob in this area, but I don't want to pay for a tech to visit.

I have a stay-at-home job. I work as a remote salesman who heavily depends on the internet 85% of my job and day-to-day. At the end of my work day, my internet decided to stop working.

I possess a Netgear AC1750 C6300v2 model and it is fairly new (purchased brand new within the last 2 years). All of the lights are lit green and seems to work properly from a visual standpoint. The issue is none of my devices are picking up the network. If they do find the network, they will read "Network is not connected to internet."

I ran through the typical reboot method. Turn off the router, unplug the cords, wait, plug back into router, restart. I attempted this twice before contacting customer service. Tried it 3 times with customer service, no avail. They ran diagnostics test and said the connection is great and everything is working....but it's not.

So I've spent all afternoon and evening trying to find a solution. Could anyone help? Does anyone know what the issue could be? Thank you so much in advance!