Sim Unlock Menu on LG G5 T-Mobile

Hello everyone
Please forgive my lack of knowledge on this subject.
I have a sim-locked LG H830 T-mo and managed to get an unlock code, but I can't get the sim-unlock screen, I've read somewhere that it's not possible to access that menu on new T-MO phones, the unlock app just tells me that my device can't be unlocked, unfortunately I'm overseas and bought the phone on Ebay that was supposed to be unlocked, now because I'm a world away sending it back would be my last resource, so I guess my question is, If I root and Install TWRP Recovery will I be able to reach the sim unlock screen?

BTW, IMEI is clear

Thanks in advance

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