Great question! Are you teaching the AP version of the course or a non-AP version? If you are teaching the AP version, there is a secure AP test you can get access to that might be a good cumulative final for you to consider.
Otherwise, I would highly recommend a final project as a semester final. In the past, I have had students create a project the week or two up to exams and then share it in a presentation during the scheduled "final" time.
It is a nice way to end the year and not so stressful for students. Students seem to appreciate the freedom to apply what they have learned in the project.