The bootloader might be unlockable, yes, but it won't be unlocked from the start. Enabling Unlock OEM doesn't in itself wipe anything, but only allows the bootloader to be unlocked. When you then unlock it, your data will be wiped.
I understand the differences between unlocked bootloader from factory and bootloader which could be unlock.
But as I said previous Samsung S4 and S6 Edge, got unlocked bootloader from the beginning.
I didnt unlock them and that would be necessary if they was locked because I installed TWRP on them.