When combined with Davx5 it will sync to a server. Integrates with calendars as you desire, I think (my workflow doesn't include the time blocking but the tasks show up on a calendar and you can specify their duration but I'm not certain about the time blocking).
I'm using Tasks.org with DAVx5 (android) and an external Nextcloud hosting.
You can set blocks of time, nested tasks and it adds them to the Nextcloud calendar. I think Tasks.org can sync with Google Tasks, but it has limitations.
My only step left is self-hosting Nextcloud.
How can you control duration of calendar entries?
When creating a task, you can choose a Start, End Date and a Timer.
You also have to select the Calendar where you want Tasks.org to save your task.
In Nextcloud is the same while creating tasks, but it'll create a Calendar for every list of tasks (e.g Personal tasks, College tasks, etc)
Ah, that explains it. I removed the "Start time" field for tasks because I never used it, and then forgot about it.
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