Unreliable home internet

How distressing for you, and puzzling. Your metrics are good to excellent. You should be getting speeds of over 200Mbps down because you have the more desirable n41 on the Secondary (5G) and a good signal strength.

If you have an external router plugged in, try it without it plugged in, just using the gateway’s built-in router.

It is easy to reset the gateway's connection by restarting it via the button on the side, after making any changes and just to refresh things. I've read that the Modem Storage message on the top of the gateway doesn't mean anything. Some people got rid of it via the reset.

If you aren't using an external  router, and you have a laptop or computer with an Ethernet port, plug the computer into the gateway that way with the provided CAT cable, thereby bypassing the wifi to rule out wifi being the issue. If you got speed that way, you will know something is wrong with either your wifi setup or the wifi function of the gateway.

When setting up your system, it's good to get one device working properly, before adding all the smart devices on. Since you were trying to set it up when the tower was undergoing maintenance, you could try a hard reset of the gateway and starting all over again. By hard resetting, I don't mean just restarting the gateway, but by depressing the reset hole at the top of the black insert panel on the side of the gateway, using a paperclip or pin, holding for four seconds, and releasing. Then you will need to re-enter all your setup data. I think if you haven't done it, a hard reset like this is worth trying, given that you set up the thing at a time the tower was not functioning properly because of maintenance.

Do you by any chance have a 5G phone on T mobile, or a friend who does, and does that work at your house doing a speed test? That is a sure sign, if it works well, that you have a problem with the gateway and need to request a replacement.

One more thing I thought of...you said work on your tower has come and gone, according to a service rep you called. What kind of time are we talking about here? A few days, a week. Their tower maintenance issues can last from a few hours to a month, it seems. If they did a new n41 installation, the tuning of that can take days. Perhaps someone who knows more about this stuff than myself can clarify, it it possible to get these kind of good metrics and there be something missing with the connection to the backhaul or something, that would account for getting a 1 or 2Mbps speed?

Another thing, I used to have my DSL modem/router two rooms away and it worked fine, full speed. This gateway's wifi will not work that way. You need to be 20 feet or less from the gateway to be sure the wifi will reach you full speed.