T-Mobile Home Internet throttling speeds to certain servers (10x reduction)

After close to 3 months I still have no fix for this issue. 4 calls to T-Mobile with the same results. I bought a GLinet Flint 2 MT-6000 router that lets you ad a VPN inside the router. I use Surfshark and wineguard and when it is on my speeds using speedtest.net are close to 200 down, when the VPN is off the speeds are 6-10 down. This means the reason they give, towers being worked is complete BS and I am being throttled. The speed does not go up when the cycle starts over, I am just being throttled. I use about 2 tig per month so heavy users are being throttled.