Title says almost it all: I am not sure how to set up a task that will be deferred to next Sunday 8pm, and will repeat every Sunday at 8pm, no matter whether I completed it or not. Like a reminder actually. I’ll want a notification for the task, so maybe I also need a due date?
Welcome I think you answered your question, you need a reminder to think about a task.
You can set a repeating task and drop an instance of it if you decide not to do it and it will pop up next cycle. However the aim is to complete tasks not constantly drop them.
One way is to word the task “consider doing x” that way you can consider doing it, or actually do it. It sounds like cheating but if used sparingly it is quite effective.
For example the rubbish may not need emptying but a task saying “consider emptying rubbish” can be completed legitimately even if you do not actually empty anything.
There’s no way to do what you want. OmniFocus creates next week’s task when you complete or drop this week’s task. In all cases you’ll need to interact with this week’s task.
I use the Due app for this kind of task so it comes to me and I can decide whether to do it or not, then complete it and next week’s task is created.