Is there a way of making units in a course or quizzes within a unit optional so that it doesn't stop a learner earning an award where the requirements are set as 'Visit all content modules'. I can't see the option.
I appreciate your interest in this issue.
I have conducted a brief test where I created a course with one module. Inside the module, I added 4 topics but only marked 2 as required.
As a test user, I accessed only the compulsory topics (2 out of 4).
My test user obtained the award after visiting only 2 mandatory topics.
Note: the award release condition was "Visited all content topics".
I hope this helps!