adb – Boot twrp with fastboot gives an error

I am trying to use the fastboot command to boot my ported twrp for my moto e6s, but when i run it, it says:

> fastboot boot twrp.img

Sending 'boot.img' (28774 KB)                      OKAY [  0.978s]
Booting                                            FAILED (remote: 'unknown command')
fastboot: error: Command failed

Any idea why? My bootloader is unlocked and no I don’t have fastbootd
I really want to test if it boots before I flash it, because I don’t want to flash a custom recovery without booting off of it first.
I used the command fastboot boot twrp.img