Slow 4G connection only, but only sometimes -- SOLVED

I have been using Tmobile home internet for about 3 years. No problems until June 30 right before the 4th of July holidays. i noticed that my internet connection went to excruciating slow to no internet connection at all! i am about had it with Tmobile home internet. I have been calling customer support to help but to no avail. They gave me a replacement "cylinder" antennae (Nokia) but its the same. It is excruciatingly slow in the daytime and very fast at night between 12 midnight to 6 am. My guess is - there are now a lot of Tmobile Home internet customers/users in my remote small neighborhood and is now congesting the internetwork during the daytime when everyone is on the internet. But i cannot afford to have no internet nowadays!, Ring Cameras (doorbell and Spot Cam), 3 FireTV sticks, Lynksis Cams in my Garage, Smart Lights, Smart speakers - all these will be useless without no internet connectivity! I will try what you suggested - moving it to another place - last try this week and see what happens. (i already tried 3 different rooms in my house) Most likely i will be forced to get back in the more expensive generic fiber company here in our small community - UIA company. :-(