Tips and Tricks for Defeating Dargrul in Mythic+ Neltharion's Lair

wowhead.com:

For Season 2 of Dragonflight, Dargrul in Neltharion's Lair received a few updates and buffs for his return to Mythic+ that may change how players wish to approach this encounter compared to his Legion version.

First, while this is not a new mechanic, the damage that Dargrul inflicts from Magma Breaker is now much more significant than it used to be back in Legion. As such, excessive boss movement can now potentially lead to the death of group members, especially when combined with other sources of damage. Second, the previously listed point is particularly relevant when summoned Molten Charskin enemies now also have the Magma Breaker ability with the exact same tuning; they did not have this ability back in Legion Mythic+. And so, Molten Charskin movement is now also something that can be dangerous for the group. Third, back in Legion Mythic+ crowd control and knockback effects could be used on Molten Charskin enemies to either restrict their movement or to quickly knock them into Crystal Spikes (giving them the Crystal Cracked debuff) without them having an opportunity to move themselves (which would allow them to do more damage with Magma Breaker). However, Molten Charskin are now immune to both crowd control and knockback effects, making their movement unrestricted outside of the Magma Breaker debuff or a non-tank player attempting to tank their potentially lethal melee attacks for a period of time.

As for Dargrul himself, minimizing his movement is fairly straightforward and is controllable by the tank. The main thing to keep in mind is that, since Crystal Spikes spawn on the location of random players (with a preference for ranged players) and all melee players