I’ve been a paying Todoist customer for many years. For some reason, they steadfastly refuse to introduce blocking/blocked by flags.

It seems so strange to me to do all the hard work of allowing arbitrarily nested projects and tasks, sub-tasks, labels, complex filters and collaboration, but then not do dependencies. Imo dependencies is the big difference between something you can use on complex projects, and a “mere” to-do list - even one with nested projects, labels, filters, whatever.

I thought that perhaps I wanted a Gantt chart tool and spent a couple of months going down that route. At least in my experience, though, what I actually wanted was just some way to establish a DAG - I didn’t even necessarily need a way to visualise it, just the ability to group and filter on it.

Vikunja looks interesting - open source, self-hosted and supports dependencies/relations. No iOS mobile client at this time, though.

This. To me, it seems like a weird market blind spot. Most of the tools in this space can't even do a proper tree - typically they limit you to 2-4 levels, like "project", "task", "subtask" and "checklist". The few that don't, stick to the tree model, even though work naturally structures itself into a DAG.

From the other end, I know MS Project has pretty much all the things you need, but has questionable UX, is quite buggy (I've personally managed to brick it after running auto-scheduling on a project with ~20 tasks...). There probably exist tools with the correct representation, perhaps even better UX - but I've never heard of any. Neither did a project manager I know, in a decades-old company with well established "classical engineering" culture, which includes all the PMBOK-related concept space.

And if I'm doing my semi-regular project management rant once again (a subset of more general ranting that, on Mastodon, I started to tag as #ItsAGraph, #NotATree), let me pile on some extra wishlist items: counterfactual modelling, conditionals, probabilities. That is, expressing the idea that there are alternative strategies to pursue, and which one to take depends on information available only partway through the project.

It's a generic note storage (with a DAG based model) that's very extensible and comes with a demo task manager implementation: https://github.com/zadam/trilium/wiki/Task-manager