A running txt file for each project/work capsule has been wonders. Then common txt files for anything you learned or, things you need to learn, notes/todos, etc.

I think I would be half as productive as I'd like without this.

Yes. I have started doing this with an Obsidian note for each project. Any ongoing lists go there, and each day has a heading with todos and thought process while solving the todos. Then in my main todo list or kanban I just link to the project with one sentence on where to resume the next day.