there's no point at which Jews don't refer to ourselves as a nation/people (עם, אומה), but the Hebrew word for religion (דת) seems to have first appeared in the comparatively later-written Book of Esther, and is a Persian loanword (distantly related to Latin and English "data").
there is, of course, earlier mention of the Jewish people worshipping "other gods" which obviously refers to other religions, but this only goes to show that Jewish peoplehood/nationhood is not dependant upon religion.
or at least that the relationship between the religion and nation is not straightforward
Sunbeam City is a Libertarian Socialist solarpunk instance. It is ran democratically by a cooperative of like-minded individuals.