Seth Godin talks about tribes in his book, called, well...Tribes[0]. Worth reading. He has a few interviews on Youtube where he talks about finding your people (if you don't want to read a whole book).

[0] https://www.amazon.com/Tribes-We-Need-You-Lead/dp/1491514736

Suggested readings:

"The Culting of Brands" - https://www.amazon.com/Culting-Brands-Turn-Customers-Believe...

Blueprint for Revolution (as mentioned in Adam Grant's Originals) - https://www.amazon.com/Blueprint-Revolution-Nonviolent-Techn...

Tribes by Seth Godin -https://www.amazon.com/Tribes-We-Need-You-Lead/dp/1491514736

The True Believer: Thoughts on the Nature of Mass Movements - https://www.amazon.com/True-Believer-Thoughts-Nature-Movemen...

I've read the first three. The fourth is on my short list. The common theme? Start in a tight niche and establish a core of "fanatics". With a niche and a core your odds of traction and sustainability drop off.

If it helps, use any major religion as a reference point. That is, Christianity wasn't always the dominate (?) force it is today. But it started very small and tight.

A community isn't much different. Perhaps less extreme (?), but the same basic elements remain.