> That sounds a lot like work.

Correct. This is why the Product Manager role exists - to define "what problem are we solving, why, and for whom?" by engaging with the market. But if you already know what problem you want to solve (for yourself, or for fun), don't bother. But also don't expect others to pay for a solution to a problem they don't have.

> agile poker and code commenting and stuff

These are tools for team collaboration and business planning, i.e. when there is more than one person involved in a project. You don't _need_ them for solo projects (although I do think code commenting is still a good practice even for solo projects).