My project has involved neighbors, family, and even a few contractors. But unlike a barn built from scratch there are a lot of random bespoke tasks. Many of them require judgement and experimenting to make it work. Sadly the property was neglected a long time, and poorly built in the first place. Bulldozing and having a new house professionally built would've been faster, produced a better outcome, and only been moderately more expensive--in hindsight.

There’s Habitat for Humanity which I think would fit this description.

I’ve personally never involved myself with it but over the last few months the group built a modest house on a small lot next to my ex-spouse’s place. Every weekend I saw a group of folks (ranging in age from early 20s to retirement) there building, chatting and generally being very friendly with one another. Really cool to see.

Most of my friends don't like doing manual work, they think it's below them unfortunately.

There's just one that really loves to do it, the rest would feel exploited.