So thanks to @j4nn we have temp root shell on Korean LG V50 and as a next logical step is to deploy and install Magisk.
Thanks to this thread and @logan2611 script I think this is possible and so far using it we were able to achieve Magisk installation status checks as per attached image.
Sadly, we have afterwards trouble with Magisk manager registering and granting needed permissions as per app su request:
21617 23899 W Magisk : su: request rejected (10458)
UPDATE: Thanks to @j4nn the solution was found and implemented here
This thread can be closed.