Final update. I tested a bunch of things again today (include factory reset multiple times) and finally gave up. I will mail the router back to the seller tomorrow. At least now I know which brand to...

Updating the situation, the router just rebooted when only my macbook was connected to it, so I don't believe the chromecast and smart tvs are the issue. Honestly I'll probably just return the router...

@Solla-topee Apparently the router did not reboot for the whole night. I can say for sure it did not reboot for the last 2 hours, as it is the only time I can see on the syslog. Is there a way to...

@Solla-topee I live in Brazil, and I am using the original power adapter. And I can change it to router mode, I just changed it to test. My ISP is TIM and I'm using the Archer C6 connected to my ISP...

I'm already on the latest firmware version according to the tp-link support site

@Solla-topee It is a chromecast 2 and it is connected via wifi. The router was only stable when my macbook was the only device connected to it via wifi. As soon as I started connecting to my smart...