Question about bootloaders

Hey, I'm thinking about getting this phone, but could use some clarification. Could I in some way achieve unlocked bootloaders starting with the latest version? As in, if I were to buy the phone now, would I have any chance of being locked out of installing a custom recovery and rom? I'm coming from a galaxy s4 and am kind of paranoid because of how the bootloaders are impossible to unlock past a certain firmware.
Thanks in advance, sorry if it's a dumb question