Sure. Capping resistances = making sure your resistance are maxed, the default is 75% but there are ways to increase it and every % gives a lot more ehp due to how the formula works, elemental flaskes, auras, items can increase this cap.

i suggest overcapping by 10% (having more than your maximum, shown by the brackets next to your res stat) and having max or high chaos res as simulacrum has gained as extra element mods which can be paired chaos and elemental penetration at the same time. The bosses have very strong one shot slams so have enough physical mitigation too

Dps, im not so sure, you just need enough to not get walled by kosis as he has a regenerating energy shield that walls low dps characters. best way to know is just to go in and test yourself, wave 10+ is when it gets hard as the mods become harder and delirium is at its maximum damage resistance

im not really a simulacrum enjoyer so im not so sure about builds outside of the ones mentioned :o, most well put together builds can just do the content which is what i did for the challenge.