obviously, I mean it be too fast & absurd if she instantly gains strength that rivals the Demon King after defeating Mother. Sure Mother is super strong but there is definitely a gap in the power between Mother & the Demon King. I mean if there wasn't then she wouldn't bother contacting the Demon King in the first place. I mean, sure Mother was bent on getting rid of Komuko and she still has the strength left to do so despite the degradation but she wasn't betting all her chips on that and called for desperate measures which is very smart. Mother is aware that Komuko killed that certain Earth Dragon which is a very formidable foe and that fire dragon as well. She clearly knew that Komuko is not gonna be easy to get rid of. Also the level gap between Mother & the Demon King is large so even if Komuko killed her, I doubt she get to the same lvl as her afterwards. The higher the lvls, the steeper the curve is.
Also the huge thing that gave Komuko advantage is her immortality. Komuko's life could have ended right there had it not been for it.
can someone tell me the chapter on the novel where kumoko where starts to battle '' MOTHER ''