I selfhost Vikunja on a small 1GB RAM VM. It has views for list, table, Gantt and Kanban (I assume that's what you mean by not manually reordering?) You can setup reminders for your tasks like any project management tool as well.

You can access its web interface via port 3456, so no syncing or external app is needed, it's all browser based. Of course, you can setup a wireguard VPN to access it anywhere.

Like a project management software?

There's Openproject and Leantime... not sure if its what youre looking for though Both self hostable

Welcome!

Here's one that I have saved:

https://github.com/offa/android-foss

If you want something super simple to generate a calendar, you can generate Gantt charts with PlantUML. There are more complicated tools out there that try to replace Microsoft Project, but personally I haven't found anything really worth the extra UI vs the simple text markup source file for plantuml. (ymmv)

https://github.com/cornelius/awesome-open-source

YouTrack can be self hosted. But it may be complete overkill. It has kanban boards, a ticket system, ganz charts, everything you might want.

But you don’t need to use all of it, it can be used in parts as well.

/edit: it’s not open source though, sorry…

Project Libre: https://www.projectlibre.com/

I have to ask first, did you mean a task management software or floor plan and such? (Especially since you mentioned aligning things manually)

Maybe https://dotproject.net

I like Vikunja