Forcing Voice Network Type to GSM? While Keeping Data on LTE

[MobLotus]

Hi I am currently using a Samsung S7 Edge SM-G935K (South Korea KT Model)

This is a unlocked phone that I brought to the United States to use for the next half year or so. I am currently using a MintMobile Sim (cheapest for the duration of time I am staying in the US) however I am experiencing problems while dialing and receiving phone calls.

After a lot of reading on the forums and talking to customer service, I think I might have found the problem, I am simply having a problem connecting to some of their voice bandwidth.

https://www.frequencycheck.com/carrier-compatibility/N5XGFNZ/samsung-sm-g935k-galaxy-s7-edge-td-lte-samsung-hero-2/mint-mobile-united-states

After some fidgeting around with Network Connection I realized if I force my smartphone to only stay on the GSM Network Type I have no problem with receiving or dialing numbers. If I stay on the LTE network I have no problem using data however Voice Network seems to go all crazy and not work.

Therefore I was wondering if there was a way to keep my Voice Network on the GSM network type while having my Data Network stay on the LTE network?

Or if anyone knows of any other solutions.. I am all ears.