There were some dungeons in Resurgia that are worth farming for materials and some drops. And then there are those that are Kazuki's guild's target to clear and monopolize. I listed at least ten dungeons that are going to be qualified to be on the list. I have ignored Kazuki for quite a while after he failed to gain a position during the Pioneer quests and I bet that he already cleared a few of those 10 target dungeons with his guild members. But I am certain he hasn't cleared all of them yet even though he has a lot of time.
These dungeons are very unforgiving in parties with large numbers. They don't just allow players in and out without giving them a real challenge. Kazuki only managed to clear these dungeons in the past timeline in 4 months after monopolizing them. If he is still as slowpoke as before, I have found a dungeon he will have a hard time clearing but a great find for us who needed a quick clear and quick grab of materials and experience.