`fastboot oem unlock` results in unknown command (Alcatel 1s)

I have an old Alcatel 1s (5024d) with Android 9 and I wanted to try my hand at rooting it. I've been following a tutorial that's supposed to let me flash a boot.img patched by Magisk Manager. I've enabled USB debugging and OEM unlocking in the developer options, installed the necessary drivers, and have downloaded the official platform-tools to be able to use adb and fastboot. Additionally, I also have the original cable that came with my phone. I have zero problems finding my device with and adb with fastboot, but when I try to use fastboot oem unlock (when my phone is in fastboot mode and connected to my PC), it just shows

FAILED (remote: 'unknown cmd.')
fastboot: error: Command failed

I have also tried fastboot flashing unlock, but that shows

FAILED (remote: 'Not implemet.')
fastboot: error: Command failed

There's frustratingly little information about rooting this 1s version, so I'd be grateful for any advice on how to unlock the bootloader.