I turned down the router rent, I have a Google Nest Wi-Fi. Router is plugged into the wall in the living room, then I’m running this cable: https://www.amazon.com/Ethernet-Cable-Meters-Network-Internet/dp/B00GBBSRKW into this box https://www.amazon.com/Android-Amlogic-S905W-Support-Ethernet/dp/B09D8ZV696 and I usually watch some live streaming or tv shows on it.

The ethernet jack in the wall - did you confirm that it’s wired and terminated properly? Did you try connecting your Nest router directly into the ONT and confirm the bandwidth you are getting?

Should I get a new router? Is there a better cable I could use? The guy was in the closet I guess that’s where the ONT is and the google nest flat wire is going from the wall to the router. Everything is within a foot from eachother.

No you don’t. Try the troubleshooting steps first.