I´m not able to make my comments visible on my secondary display while I´m in presenting mode.
Comments are designed to help create a presentation, (they are made to look like yellow disposable sticky notes), they are not designed for in show use as the comments contain notes unsuitable for the viewer, and therefore do not appear during playback.
This is a "showstopper"! Literally!!
This is about using the right tool at the right time, if you want to show additional text, use the custom text box and add text to that.