Working full time for someone and doing a side hustle is hard, from experience.
What I’ve found is that trying to do the side hustle takes away from a lot time spent with your dependants, which you will never get back, unless you are lucky enough to “make the break”
Not impossible, and you’ve got to try and find a balance. But it just may never happen.
I'm fortunate that I don't mind getting up early and I hate morning TV/radio/news, so I can find an extra hour for myself each day.
As it's being done collectively, there's more of a chance of it getting off the ground, as people could take turns working on it in their spare time instead of a side-hustle dominating your time.
Once it's established, those people could then quit their job and work at the coop.
There are credit unions that could help with startup costs, as well as guides on how to structure it based on other successful coops.
Potential issues: employers don't tend to like it if they get wind that a group of employees are doing something on the side, and may find reason to take ownership of said effort (which your contract might allow them to do).
If all you optimize for is the well-being of your family, your efforts should go into amassing wealth, not changing the world.
So I'll ask you straight out: why is the choice you've made salary man or nothing? Why can't you get started with a side hustle, and then if it gets traction, you can quit your job and it becomes your main living?
One of the big barriers to this is a lot of investors seem to expect founders to work for nothing in the early years, which is a pretty privileged place to be: most people with dependents just can't do that, so I hear you.
But you don't need VCs. You don't need to live on noodles. You can build something that replaces your day job, you just need to figure it out.