5G Home internet agonizingly slow

My 5G Home internet has been agonizingly slow in the Huntington Terrace neighborhood in Bethesda MD for about a week now. I called T-Mobile who first told me that everything is hunky-dory, but 30min later admitted that they had ongoing maintenance work on 2 nearby cellphone towers for the past week, but have no idea how long the maintenance work will last. 

I have lived in Africa for the past 6 yrs and never had such bad and expensive internet service. Can someone pls provide me with recommendations for a better provider?