This feels like the author said “hey that’s a cool title! I wanna make that the premise”, but then wrote the story and thought “hmm, yeah on second thought it’d make more sense to just make this about her coming to the world, being a slave, getting free, and making a life for herself... but I already made the title...”, and then they just mashed two storylines and premises together all at once without giving either the proper focus.
This could be a good story if it started from her coming to this world, how she became a slave (because that wasn’t mentioned), and her harsh conditions. Then it could go into detail about how the mistake was made, she freed (and ran), and then have the witch looming over her fir a cliffhanger. Then future chapters have her learning magic and to live from the witch. Well, that would work for one chapter if the chapter was long (at least 50 pages), this also felt super rushed. Or this could be good (option two), if it started with her meeting the slave and choosing to purchase him and then overtime have hints and flashbacks and dialogue to explain her personal past and why she bought him. It’d be extra interesting if it was fro, the perspective of the slave that will be bought and we got suggestions that the witch that purchased him is an other worlder. This weird mashing butchers any potential plot or storyline.