Is it official? We prefer english names for chinese copyrights if they have an official translation.
It is official, and for that matter, the official English name of the MDZS books is Grandmaster of Demonic Cultivation. (Though the fandom seems to strongly prefer MDZS / Mo Dao Zu Shi, while I've seen CQL and The Untamed used in about equal measure.)
Honestly, we could do with a general thread for CN -> official EN, which I guess this could become if OP doesn't mind. There's a bunch floating around with EN titles that currently use the CN romanization instead, which is inconsistent with the standard:
I would make one big BUR but I hesitate since some of them are huge. I guess I might start by doing some of the smaller ones. Some of them also have the issue of already having a bunch of qualified character tags that use the CN name, like Honor of Kings. In my expand above, I put an asterisk if they're complicated by having implications or a bunch of qualified characters.
...If I find any more, I'll add them to the above list, I guess.