Serca nightmare requirements

I've heard it's whalebait but just how whalebait? What are the expected cp and dps requirements for Serca nightmare mode? Both real requirements to clear and what you think party finder will be gatekeeping at.

My main is 1740 with almost full ark grid, +25 weap, adv honing max, lvl 9 doomsday gems and 8 on the rest and about half of the expensive books done and comes out to barely over 4000cp. Is she ready? Is it close enough to be worth pushing or should I focus on getting some alts up for hm?

Also would clearing tfm for the title help with gatekeeping or is death incarnate chill?