Nope, sorry. Since the bootloader of the Meizu M3 MAX is locked, we can't install any mod or custom recovery. There isn't a Bootloader Unlock guide available yet for this device since Meizu never released its source code. Sorry, I have your same device ;)

Custom Bootloader has blocked on meizu Flyme OS for phone security

yes i found a method to unlock bootloader and root the phone. i also made twrp but you have to install flyme 7.3.0.0A here is the update.zip: https://www.mediafire.com/file/gzfda0odbwunyh2/update.zip/file here are both guides: https://forum.xda-developers.com/t/guide-meizu-m3-max-unlock-bootloader.4588687/ https://forum.xda-developers.com/t/guide-root-meizu-m3-max-magisk.4588697/ and here is twrp(only works with the update i sent): https://www.mediafire.com/file/7q0apjvatf1d3db/twrp_m3max_flyme_7.3.0.0A.img/file you will use command "python mtk w recovery twrp_m3max_flyme_7.3.0.0A.img" you will see where in the guides.

Meizu M3 Max i no longer locked, i found a method to unlock. here is my guide: https://forum.xda-developers.com/t/guide-meizu-m3-max-unlock-bootloader.4588687/