Massive fluctuation of internet speed

I have a quad booster antenna i spend $400 on to amplify any TMobile signal from 3G to 5G UC  mounted on my roof pointing straight to the cell Tower 2 miles away, right now I have tree bars on 4G but no Internet connection, but 5G UC on my phone? My home Internet  system swings from nothing to 350 megabytes, it's always worse in the afternoon, I also live out in the country side far for everything, I had Starlink before but Elon Musk crapped that up making rural use more expensive and drossel down speed, then I quit, I have to check AT&T and Verizon and other nearby providers as TMobile does not fix a ting.....Now it has been like this for a half a year, I'm sure Tmobile know exactly how to fix it but won't spend time and money to satisfy their home internet clients, once upon a time TMobile was good, now it look like the company's budget people are in power running profit over customer service!