I went to a girls school. It also happened to be an RC school, though you didn't ask about that.
I don't have kids though.
Having turned my back on religion I wouldn't send my (imaginary) children to a faith school and think religion should stay out of school, bar basic information about various religions.
As for single sex schools, I'm on the fence but veering slightly towards mixed. I do think girls in particular probably do better in single sex schools, especially in STEM subjects. However, despite having brothers, i came out seeing boys as aliens and not being comfortable around them and it took me years. I think in this way my education failed me. School should be for life imo.
In my school they taught "girls" subjects like cookery and needlework but not metalwork and woodwork. They weren't an option. Our school had a 'sister' RC boys school round the corner which we shared events with e.g. discos but other subjects weren't an option, but this was in the 70s/80s so I'm sure would be illegal now.
I grew up and still live in London but a different borough. The borough I grew up in had single school boys and girls schools, though the majority were mixed. The borough I live in has a girls school but no boys school, and I'm sure the same can be said of the borough I work in. In fact that has an RC girls school and a non religious girls school.