If one wants the ability for advanced customization of the UI, one should avoid Samsung devices. Between Tizen and it’s smaller implementation in TouchWiz, they resemble Apple products... either you like them or hate them.

Even if one wanted to flash a different ROM onto the the S7, unless the ROM is built with…

With a Note 4, you may want to check out CyanogenMod 13, which has the UI tuner enabled by default, as well as a whole lot of other UI customization features.