why has my home internet service gotten so much worse?

ZolloDavid wrote:

We are long-time customers of T Mobile home internet, going back to the invitation-only plan. When we first joined, our speeds were as advertised, and we never had problems with the router freezing, performing well below advertised, etc. Two months ago, roughly, we switched to the new router, since 5G coverage had arrived in our community. We even agreed to pay the higher monthly charge ($60 as opposed to $50) so we could acquire the newer technology, despite the fact that we were customers in good standing for many years. Our service has not only decreased in speed, but it freezes constantly, doesn't allow me to use the home internet app, which shuts down and restarts constantly, and generally behaves like a much-inferior product. ... I said we couldn't go back to the old T Mobile LTE router ... When I get online to look for answers, it seems like the issues we're  having are being repeated over and over. If we could get the 40 mbps of our LTE router we would be overjoyed. Is there any advice on how to fix such systemic problems?

Sometimes I wonder why folks leave a working system, in the search of more costly unproven upgrades.

The T-Mobile Nokia 5G gateway appears to be very temperamental, with its location, overheating, limited interface options, etc.

Things you could try:

Have T-Mobile push a newer software update to your gateway (I think the newest version is 1.2003.03.0178).

Have T-Mobile exchange your gateway for a new one, hopefully with newer firmware.

Try providing ventilation to your gateway, in case it might be overheating.

Or, ask T-Mobile for the older stable 4G LTE gateway (which you had before), which appears to still be available for those who only have 4G service.

Thanks for taking the time to leave some advice. I will try some of those ideas tomorrow. Assuming the question at the beginning of your answer wasn't rhetorical, I think I mentioned that we had recently gotten 5G service in the area, and were promised speeds double what the LTE router was able to provide. But your point is certainly well taken. It's human nature. 

@ZolloDavid I switched from a cable modem not for the price (that was a bonus) but because the service was unreliable.  When it worked, it was faster, but when it failed, there was nothing I could do about it.  I am supposedly close to 5G towers but I think not close enough to benefit from the increased speeds.  My downloads are between 50 - 100 Mbps and my uploads are about the same.  I was having overheating problems though which required me to restart several times a day.  As soon as I set the modem on top of a fan to increase air flow, I've not had a single crash.  My hope is that over time they'll expand their 5G coverage so I can use the higher speeds.  But at least it's reliable now.

On a side note, one thing I will suggest is that they are now offering the $50 rate again for this month, call and see if you can get switched back to that rate. I do not believe they should have changed you to begin with since they were suppose to offer the 5G upgrade for free. Perhaps due to your not wanting to wait that was the only way you could get it on demand. But see what they can do now, it is worth a shot.