Need I unlock BootLoader before using Magisk to root?

[VC_Project]

Hi.by chance I have got a Galaxy S8.Because the soc on this phone is snapdragon 835,I tried to use scene4 to overdrive it.But I found that I need to root my device before overdrive.I tried kingoroot,but it doesn't work.I want to flash Magisk by TWRP.But I am afraid of unlocking Bootloader because if I unlocked it,I can't use QHD technology again.So need I unlock bl to flash magisk or flash twrp?
Thank you for your support.

 

[VC_Project]

By the way.If so,are there any other way to get root permission without unlocking bl?

 

[xcutnr1]

You can get root without unlocking BL, but only on a nougat rom.

https://xdaforums.com/t/new-method-...e-snapdragon-g950u-u1-v8-bootloaders.4060701/

Go to Telegram thread for newer method.