Random TV Buffering

@coooldad, those numbers look pretty good to me! I'd be very happy if I could get that speed. My gateway connects, at best, at 60-70 Mbps, and usually only 35-40 Mbps. Nonetheless, I am still able to use 48 devices simultaneously, including streaming TV, computers, et al. My point is that speed is relative to what you're trying to do. If your devices are operating well and are accessing the Internet at the speeds you show above, you are doing very well.

You did exactly the right thing with the Orbi! While you are adding a hop from the gateway to the Orbi, it doesn't appear to have negatively affected your WiFi signal. Just make sure that the Orbi is in Access Point mode so that solo the T-Mobile gateway is managing DHCP.

As for WPA, that is really a factor of the client that is connecting. It's a security setting for the WiFi you are broadcasting in your home. It has nothing to do with the tower. Hence, WPA3 is more secure than WPA. Some older devices can't read WPA3, which is why you sometimes have to create a new network with only WPA/WPA2 and 2.4 GHz.

Hope this helps. Good luck, although it doesn't look like you need it!