I was fortunate enough to be involved with a modern secular community that aimed to become a non-religious church: Sunday Assembly.

Take the best bits of religion, including purpose, structure, community, and tradition, but make it available for non-believers.

We even got so far as making the interview stage of Y Combinator:

https://benrmatthews.com/meeting-heroes-y-combinator-intervi...

During the interview, Sanderson (Sunday Assembly co-founder) had a brilliant back and forth with Sam Altman, but ultimately the idea didn’t stand.

I still think the ethos of Sunday Assembly has merit.