Start a task list or workflow with deadlines at any time of the day, not at a fixed time


My question is not particularly related to obsidian, but maybe some community members can help me.

I’m looking for a tool, a windows software, online, open source or paid, that would allow me to launch a task sequence or a workflow at any time.

In short, I don’t have a fixed schedule, I can start working as well early in the morning as late at night, I would like to be able to launch a recurrent list of tasks to do, whatever the time of day, with hierarchical tasks and subtasks, the first one to be done ideally before the next one and so on.

This will be useful for work, but also for my daily life, the problem is that the different tools that exist often only allow to indicate a precise date or a precise day of the week, with precise times, I need to be able, when I create the workflow, to put a reminder on some important tasks or subtasks not at fixed hours, but, for example, 2 hours after launching the workflow, or when a previous task has been done.

I hope to make myself understood, if anyone has an idea, I would be glad to hear it.