I just purchased the Unlocked Galaxy S9+ International Version SM-G965F/DS and I am using it with my T-Mobile account. I discovered that WiFi calling and a few other features don't work. As you know, the processor on this version is the Exynos and not Qualcomm. Is there a way to flash the T-Mobile Rom on this S9+ version? If there is a way, does the phone have to be rooted or bootloader unlocked?