My productivity app is a never-ending .txt file (2020)

I do something similar but with Emacs and org mode. I start a new file each time I join a new company and just keep on updating it with things as I'm progressing through my day. The one I carry right now goes back as far as Dec 2017. It's a super useful resource for dailies, or looking back at what you did. Heck I even add TODOs and shell snippets that I often find useful. If you feed it to some LLM then you can even do nice summaries and meaningful searches that aren't necessarily based on single keywords.

Yep. Org-gtd, Org-Roam and Org-journal user here. Haven't needed anything else. All local, searchable with deft and old fashioned grep.

I'm using org mode too. For time based tasks I like to get an overview of tasks and timestamped notes by using EasyOrg [0]. You can search based on schedules and deadlines.

[0] https://easyorgmode.com/docs/org-agenda