No connection, white X in yellow circle

My Nokia “lost connection” the morning of 10/04/2022 (yesterday) during a troubleshooting session with tech support for SLOW speeds the past 2 months. I could not revive my Nokia after many reboots and resets, etc. T-Mobile’s excuse was “tower upgrade” causing a lost registration and should be fixed soon….blah, blah, blah. Anyway, I suspected the worst and convinced support that the unit had died, even though it had been connecting without incident for 9 months. I also requested NOT to get another Nokia because I heard the T-Mobile Arcadyan KVD21 High-Speed Internet Gateway used different frequencies and I hoped these frequencies would fix my sudden connection problem (i.e. I suspected T-Mobile changed something on the network and my Nokia may still be alive). Fortunately, they gave me one of the two “black boxes” (Arcadyan), I registered it in the store, went home, placed in the same spot as my Nokia, it connected perfectly and now my signal is 4-bars instead of 3-bars and my speeds at increased form 20-30 down to 200 down (10 times). To be fair and important to note, I was getting these better speeds with my Nokia 2 months ago, so I still suspect that T-Mobile “tweaked their network” to the Nokia’s detriment. I whish I new the true story.