Pardon me asking, but what is your content utility for combining RTAO with lumen? Lumen is already a full-stack light transportation solver, which includes some of what RTAO does. I’m not doubting you don’t have a good use case, just seeking to understand.
If you’re looking to control levels of occlusion from lumen, you can control that in the post-process volume. In addition, color grading can be a very useful tool for controlling the apparent amounts of occlusion in a scene.