I have a course that receives individual students at any time. There are not groups or cohorts.
The course must be organized in sections (or something like). Students get access to the next only after being approved on the current.
Evaluations are done by a teachers team right after completion, so students are individually progressing section after section.
Besides all this freedom, students have deadlines. They have maximum 8 weeks (56 days) for each section. After that they must be blocked.
In short, my deadlines are not fixed for a course and activity. It's for an user and section. It's not defined by an specific date, but for a number of days.
I really couldn't find a way to do this in Moodle.
Regards.