It looks like Samsung has silently removed the option to unlock the bootloader from One UI 8.0 onwards as it has been reported by some users in the forum (here, here). By reversing the Settings app code we can take a deeper look about how and...
Page 35. I haven’t confirmed anything, so do your own research!
I just switched from my Galaxy A53 5G to Pixel 9a. Installed GrapheneOS on it and it works flawlessly.