Best Ash in the game until NG+ and beyond 'cause only the Mimic, even post nerf, scales beyond +10 due to it being based on your stats.
Tiche, and Finlay for the matter, do extremely well ng+ and beyond. Tiche's damage still hurts all things considered, and given she's a dodge maniac it's not like she goes down too quickly either. In all honesty I fell out of using the Mimic after getting Tiche, and that was before the Mimics nerf.