I've been looking into all sorts of them recently: logseq, appflowy, vikunja, etc. What tools do you use? Why? What problems did you run into with the previous set of tools you used for this job?
Right now I'm primarily interested in finding a "zero-knowledge" (cloud provider doesn't have access to my data) system for task management. Needs to be able to have recurring tasks and tasks organized in some interesting/useful ways (by projects/labels/something, maybe a kanban and table view). Deadlines and time tracking/planning interesting but not required.
For me one of the most flexible and mature way to knowledge base, tasks and notes is an org-mode.
I have two main workflows. The first one is task management. I have a lot of recurring tasks with tags, deadlines, schedules, etc. All of them are living in org-files in my Nextcloud. On Android I'm using orgzly-reviwed for sync via WebDAV, on my work I'm using organice (via WebDAV) as a "web-version" and also I'm editing my notes in emacs on my laptop (but actually any text editor could be used).
The second one is a knowledge base. I'm using org-roam locally (and with a localhost web server, built in into emacs) and orgnote for Android/Web + synchronization. My knowledge base is Zettelkasten-based.
Orgzly-reviewed: https://github.com/orgzly-revived/orgzly-android-revived
Organice: https://github.com/200ok-ch/organice
Orgnote: https://github.com/Artawower/orgnote
Orgnote provide a way to encrypt all notes by your own key/password. With orgzly I'm relying on Nextcloud encryption.
The org.pdf documentation is 300 pages long O_O ! https://orgmode.org/org.pdf
Simple, spin up a Stirling PDF docker, split the org docs and create org notes either by section or by page, linking to the relevant PDF page
Now you've practiced using org mode by documenting org mode in org mode using your own words based off the org mode documentation
Yes... org-mode is more than 20 years old... It is a price of flexibility: I have a strong feeling that one can adjust org-mode to any workflow. But I do not use even a third of the org specification. There are a lot of cool blog posts like "org mode quick start" or "org mode basics", I would recommend to start from such posts, not from a documentation.