Legacy Device Internet Connect Issue

So I need to connect to the internet for a few devices thay are over 10 years old. Unfortunately I cannot seem to find and connect to my AT&T router. It is a 5G/2.4G tower BGW 530 900. I tried to disable bandsteering, renaming my 2.4G network, setting up the guest wifi and even Hotspot my phone.

Does anyone have any ideas on how I can connect to the internet?