The hardest thing about making creative historical films is finding authenticity. Some eras can be hard to find proper information from.
That’s when you need to find an expert. In this video by Rachel Maksy, Dr. Colleen Darnell, a renowned egyptologist, breaks down the good, the bad, and the ugly of the 1999 The Mummy.
Is the film really that bad? The good, the bad, and the ugly is accurate for this particular film as far as historical accuracy goes.
I hope this helps you learn to find the balance between the history from which you draw inspiration and your tenacious vision.