I do have a 4k tv, and a 1080p one. But personally I don’t see big difference on 720p vs 1080p vs 4k. I have to be like 4 feet from the tv to notice it. 720p is sufficient.

I also did this, I feel it’s better this way. Also the modem restricted me in so many ways. Now my cheap router gives me far more freedom and control. Forwarding ports, no problem. DNS change, no problem. Other SSID, no problem. A separate isolated SSID for visits, absolutely. And if a I change ISP I only have to connect the new modem and no need to change any of my devices.