I want to add to the users who reported this behaviour from their home internet. Of note, customer support is of no help (is it me, or has it become useless to contact them over the phone?): the issue is often misclassified (“slow speed”) and they have no idea what is going on, just randomly saying “the tower is under maintenance” (for weeks at a time?).
If you need reliable internet, T-mobile is not for you.
(fun fact: my connection dropped twice just as I was writing this message)