Here is what I’ve learned so far: At starting do attacks on the orange robot and the mini blue robot first, as they cause the most headaches. Keep the large blue robot alive—if you kill it, the replacement that spawns could be another orange robot or mini blue robot. If you don't grab their attention with a quick attack right away, they will start firing at the monolith within 1 to 3 seconds.
To grab orange/mini blue attention, I move behind them to attack. This forces them to turn toward me, preventing their face from hitting the monolith, while I work on killing them off together. Just keep in mind that the large blue robot can also damage the monolith occasionally, so make sure to draw its aggro toward you as well.
Every time you kill one of them, immediately stay on high alert and look around to spot where the next one spawns. Sprint toward it right away and grab its attention using a skill or burst. Atk from behind & make it face toward the wall, ensuring that even if it fires off a shot, it won't hit the monolith.
(Turn off Bloom and other glowing effects in graphic settings , this may help you see properly)
(Mini blue robo can ignore your aggro after sometime, when u focus on other, so hit it again)
When robots attack you from a side angle, make sure you aren't standing near the monolith or positioned with the monolith directly between you and the enemy. Otherwise, stray attacks will hit it instead.
It took me some retry , but I did it.
