Speed Drops the regains and restart ?

OK so maybe we have something. I wonder about that tower. The speeds you had were more indicative of 4G LTE only NOT 4G & 5G both. I have to question if you had both the primary and secondary frequencies. If they reported they were working on the tower they may have been working on what was one of the prior Sprint towers and adding the n71 cell equipment. If the speeds have jumped up in a significant way that would explain the difference. The B2 primary is 4G LTE and the n71 secondary is the 5G NR gigahertz frequency. It is capable of pretty good speeds. Not like the n41 but in good conditions and being not too far away you might get 150-200 Mbps downloads. The B2 will primarily be handling uploads. I am just speculating but it is probably because the secondary was never right and they fixed it or they added the n71. Run speedtest.net and check your speeds and ping latency. It sounds promising.