Unlocked s21 Ultra showing as "Unknown Device" and not supporting 5G or Extended Range LTE on My Mobile account

How did your phone get locked into T-Mobile just by putting in their SIM card. I ordered one from them and put it in and after a quick update my phone shows it's on their network but it's not locked. I can easily swap my SIM card. Plus when I had issues connecting I have them my IMEI number so they have it but it still does not show any info. But my wife's iPhobe does and both our phones (S20ULTRA for me and iPhone XS for her) were bought unlocked directly through the manufacture and we're initially on Verizon for 2 years before we switched to TMO. So there no rhyme or reason here.