#1 complaint of cerec users is that Inlays and Onlays don’t fit.
#1 reason for the ill fit is a lack of draw amongst the exit angles.
If you are a beginner with inlays and onlays keep your exit angles to just 2 as it is easier for you to achieve draw amongst them compared to having more than 2 exit angles. Having more than 2 could get complicated as every exit angle needs to draw with each other.
Once you have a few inlays and onlays under your belt and understand how to achieve the draw it gets easier to achieve better fit.
Keep CADCAMing