So it's been more than a month since I have been using a monolithic journal. Including each of the tasks I need to do on a daily basis.
I did it because it was overwhelming to use a to-do list app like Things every day. I almost have too many tasks that make me anxious and feel like a failure from time to time.
But having only a journal and keeping track of what I think and the tasks that I need to do also have some drawbacks. Sometimes I am not sure I am working on the right stuff, and I want to invest my focus energy on the things that have benefits in the long-term scale. When I used the Things app, I got that because every task is part of a specific project.
And today, I think I got some insights to do it better and make me calmer and 10% happier:
First, use the Things app by default, but limit it to 10 tasks each day. If that means I will miss working on some exciting things, so be it.
Second, projects related to feature development or something relatively big projects at work don't need to have each task dated (especially to "today"). Just give the project a deadline. I can always open the project page when working on it at work.