Working with others is definitely important for motivation and for technical progress.
> I’ve tried teaming up with people on projects but it seems like if it’s not tied to a paycheck they flake out pretty quickly.
Maybe something like contributing to an existing open source project or doing some small projects of your own (e.g. writing a blog about smth that your really like, without aiming to monetize it) could help.
The best case scenario would be to start a self-supporting company or something of that sort.
I’ve tried teaming up with people on projects but it seems like if it’s not tied to a paycheck they flake out pretty quickly.