I think she’s siding with herself she doesn’t seem to have much loyalty for anyone apart from her sisters, especially hathor. I think she just wants to see everything go into chaos because she feeds off of that.
Within the original ancient egyptian myth, she was independent. Ra had to get her drunk to stop her from killing humanity, so I guess she'll be stubborn and act on her own.
I really want to know who is Sekhmet siding with... Is it Ra or she has her own agenda? Can't wait for S3