Is tmobile slowing down my data?

I'm a heavy data user, I'm talking 500+ gb a month. I pay for the Go5G plus plan so I have unlimited premium data as what a T mobile rep has told me before. Why is it when I'm using my service out of no where my phone will drop from 5G UC to just 5G. It only happens on days when I'm using a lot of data, I'll randomly look and see it dropped down to 5G.
My spouse gets 5G UC all day and I do too with speeds of 600mbps+ but randomly throughout the day it'll drop to 5G for a few hours later in the day and my speeds will then be 12-50mbps which is a huge difference! Turning airplane mode off and on will reset it and I'll be back on the UC band for 5 mins and it'll be back to 5G again.

Is tmobile secretly slowing my data down? I've already used up my 50gb Hotspot and of course that data is slowed down but I was assured my actual data would never be slowed as I'm on the top tier plan.