It’s not open-source but Trello is like an extension of my brain. Though it may only help if you understand how use a kahnban board and some basics of project management.

Many of the things we do can be projects. You just need to break them down into small more manageable tasks. This tool then helps you track all the task.

There is a open source version of trello out there I saw it on lemmy a few days ago. I’ll post it if I can remember it.