I have no solution for you. However, in my Moodle, I do use the Collapsed Topics plugin which provides students the ability to collapse topics that they have finished. Yep, this is at the topic level, not the "activity" level.
For activities, I use "activity completion" that provides students a little "checkbox" to the right of activities. When a student finishes an activity, they can check this box. This provides them the ability to see for themselves what they have or have not completed. It is up to the instructor to decide if they want the students to check this box, or for Moodle to automatically check this box. In my case, since I allow unlimited attempts on quizzes, I prefer to let the student check the box.
For activities, I use "activity completion" that provides students a little "checkbox" to the right of activities. When a student finishes an activity, they can check this box. This provides them the ability to see for themselves what they have or have not completed. It is up to the instructor to decide if they want the students to check this box, or for Moodle to automatically check this box. In my case, since I allow unlimited attempts on quizzes, I prefer to let the student check the box.