tmobile home internet speed issues

I echo the sentiments of many on this thread who advocate class action.  My experience was that, behiing in 10/2021, I was consistently getting 300mbs down and 40mbs up UNTIL three weeks ago when it suddenly dropped to <40 down and <1 up.  Even worse, the ping is mostly >100ms and often exceeds 400ms, rendering many websites and all streaming services stuttery at best and often unuseable, even when the speedtest says 30mbs.  My signal shows 4 bars on both primary and secondary.  Power cycling everything has no discernable effect.  I called several times to say WTH, and am being told of 'service maintenance' events every time I call.  I now think they are lying.  To summarize, like many on this thread, i initially received good service (first couple of months) which then changed to crappy ALMOST unuseable service.  In the meantime, I'm crafting a complaint to the FCC and going back to Comcast (which I hate/despise/loath).  GLTA