help me figure out what to do? (long winded post but I want to get it all out there)

ok, first post on reddit but I feel like you guys are very knowledgeable and not bias,

I've been a customer for 2.5 years now, Business unl ultimate 100bhs is my plan, I live in Western Kansas, started plan with iPhone 12 currently on iPhone 11,

when the switch to 5G happened we basically lost all service, 17 hrs on the phone with customer service later the "office of the assistant of the CEO" recommended that we downgrade our phones to iPhone 11 as the 11 dosent pick up 5G, I didn't care about the phones as they were free anyways, but ever since then I've dropped almost every call Ive been on, limited data, noticeable throttling of data at 9:25pm to 4:30am every day, I just checked my current speed and its the highest I have ever seen at 9.2mbps, what course of action should I take? I run a trucking company and am constantly on the run and need a phone that at least will make a phone call, I can always call someone with wifi and tell them to google Mapquest and I can write down the directions like we used to. The only noticeable difference I've had with this is the month after t-moblie figured out I had filed an FCC complaint for throttling. I'm willing to do a cell phone booster in the trucks (keep in mind I run 4 trucks and 4 pickups so I can't be dropping a couple hundred per unit) and starlink to the house/office. but I don't feel like I should have to be spending extra money for something that they called me and poached me from Verizon saying they had perfect service in my area. thank you for your help sorry for the length