I was reading “Release That Witch,” and it had some decent science in it. It’s one of the more popular and recommended books, so you should be able to easily find it. I’m not that far into it, so I can’t promise that he won’t turn his group of young women (all witches are young and female) into a harem. So far there has been more about basic science and engineering than lewd behavior.
Basically, he used the witches magic to create simple machines and advance the medieval technology into more modern tech (so far). From what I’ve read, it matches your description.
