No issues here. Is nearly matching speeds with my other devices on my local T-Mobile network. Even if it is a touch slower, I have not hit a wall that indicates my phone is slow.I have no idea why you got those speeds, specially at the T mo store but something ain't right.
I have a Pixel 8 Pro and I live in the mountains in Las Vegas. In fact, I live at the very edge of buildings before there is nothing but hills and Lake Mead. So cell reception here is terrible until you get down the mountain a ways.
My cell reception is not great using my s23 ultra or Pixel. But I get 36 MBPS in this area on my Pixel 8 Pro. So I would not say that what you observed is even close to normal. 2 GBPS? Really. No way.