My kids (now grown) went to Glenbrook Cooperative Nursery School. It was a great experience for our family. The parents assisted both in the classroom on a rotating schedule (there was a nursery for younger siblings whose parents were helping in the classroom) and with general school tasks. There were also parent meetings and occasional events. Having parents help around the school meant that there were low student/teacher ratios, and parents got to know each other, the other kids, and know what was going on at school. I’m sure it’s changed a lot since then, as by its nature if adapted according to the strengths of the parent community.
I think the schedule may be a little less time than you were looking for. Also, the school classroom is located in a church building, but is not affiliated with the church or religion. The curriculum is secular. I don’t remember any religious messaging, or even any religious decorations at all.
https://glenbrookschool.org/about/serious-about-play/