It's been a long while since I read them, but I recall Judith Tarr's assorted books set in Ancient Egypt (she had an historical novel about Hatshepsut, and some other mystery and drama novels as well), and Pauline Gedge's historical saga novels (including another Hatshepsut novel) as being quite good and well-researched (Tarr herself is an historian by training, though in Medieval Studies). These are two of my favourite authors, though more for their other books than the Egypt stuff.
Both are available as ebooks: Gedge's through HarperCollins, and you can get some of
Tarr's backlist DRM-free from the Book View Café author re-publishing consortium. (And it appears she could probably use the money, having run into financial difficulties in recent months, with her only current source of income from her writing royalties.)
Agatha Christie also wrote a well-regarded murder mystery set in Ancient Egypt,
Death Comes as the End, which I bought years ago as part of a sale, but haven't gotten around to reading myself, though we've enough Christie aficionados on these forums that someone should be able to tell you more about it.