I didn’t catch your build comp, but if you’re playing X, Shm, Rog then know that you can SoS (sneak & hide) up behind a boss like Naggy, stand behind them and start casting your regular Malo spell first and they don’t aggro until it lands. You can then land AA malo (stacks) and slow.
Also know that you can cast AA Malo and slow while regular spells are casting. They don’t interfere with one another.
Big non-traditional perks on this server that are mentioned in the Discord that many new players overlook.
When you start getting to tougher bosses, my engagement tactic is SoS behind, start casting unresistable spell Malo and just as it is landing, hit AA Malo & AA Slow, then start chaining Cripple until it lands. Once you start gearing out, Cripple only matters for Sleeper / Seru / PoP bosses.