ok so here's an idea,
Code:
DISCLAIMER :
THIS IS ONLY AN IDEA, IT MAY NOT WORK AND MAY LEAVE YOUR DEVICE IN A DEAD STATE... I NOR ANYONE HERE ARE RESPONSIBLE FOR YOUR ACTIONS OR WHAT YOU CHOOSE TO DO TO YOUR PHONE
I no longer have this device and wish I'd tried this b4 I lost it...
but if you get the Modded version of LGup or the DEV version of lgup, you can dump the stock firmware from the device using (Dump ) option in lgup,
then, if your brave enough, take the files created specifically ( boot_COM3 ) {COM number may be different but files the same} and rename it to boot.img.
put that in the Download folder on sdcard, install the Magisk Manager app .
choose install, then choose patch boot.img and select the boot.img file you placed in sdcard.
after it's done you'll get a file called patched_boot.img.
move that file to your PC and rename it boot.img .
Now go back to lgup and choose the option ( partitions download ) choose the newly renamed boot.img and flash it to the device in download mode.
upon completion, reboot your device and as long as things went right you should have systemless root via Magisk. follow other tutorials as to how to set up your new Magisk root.
And if you've the testicular fortitude to try this and it works for you, come back here and let others know how it went,
if it doesn't work you may flash stock .kdz in lgup to recover phone, if you can find the .kdz
I no longer have the device so I can niether confirm or deny that this will work.
READ : UNTESTED
if this works out tell us and don't forget to say thanks if this helps you out.
Astr4y4L of team.astr4y4l