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/

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.

Custom Bootloader has blocked on meizu Flyme OS for phone security

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 ;)