@SMatharu It seem that your issue is similar to this one. Try following Kevin's directions in that thread to narrow down the culprit.

Have you tested your internet speed recently ? Can you post a screenshot of OOKLA speed test.

What kind of UPS are you using (brand, model) ? Usually the router will work properly with the original power supply or one with the same parameters.

@GA_Polo Do you have any ISP device (router, modem, etc.) before the Archer C6 in your set up ? If you upgraded C6 FW recently try hard reset the device (method 1) and re-configure from scratch to...

gerry41891 Some of LG Smart TVs are notably known for wireless adapter issues. A friend of mine had a similar problem. I solved it connecting the TV via ethernet cable. If only your TV has that...

@peterawilson If you are targeting wireless extender mode then follow this guide. If you are targeting AP mode then follow this guide.