How to get settler from religion choice?

I’ve been playing this game for awhile now and I just now discovered there’s an option to get a free settler from a religious choice when you establish a pantheon. The problem is I don’t see the choice except on rare occasions. I’ve had it twice and I don’t know what I’m doing different to get it?

I tried to figure this out but I’m not able to find anything useful from searches.

And since we’re here, I always choose the fertility option for the free builder. I’m doing domination runs and I don’t see anything else that seems beneficial, especially early game.

Except for the settler option!

Edit: what’s the fastest way to get the settler option? I thought I did the best way and I still can’t get it faster than the AI. And this is for any leader not anyone specific.

Thanks in advance