Before this, we have difficulties to add Hole Callouts to non-hole wizard holes that have a cosmetic thread, not anymore in SOLIDWORKS 2020.Do refer to the following example to create a hole in a plate and applied a cosmetic thread to the hole.
The answer is we use the Smart Dimension tool. How to do it?
Create a side view of the hole in a drawing, then , activate the Smart Dimension, click on the two silhouette edges of the cosmetic thread. Then click to insert the dimension.
After the dimension is placed in the drawing, the hole callout appears for the non-hole wizard hole.