Not being able to link multiple notes to a calendar event is a clear flaw and misleading as advertised at time of download. It would be easier to open event in outlook and add multiple agenda items in note section of event. Also your description of your work around are vague and hard to follow. You need step by step instructions with screen shots.
I don’t believe we promise anywhere that you can link multiple notes to the same calendar event. Also from what you describe I have a feeling that you might even mean reminders or mixing up a single list item vs a single note. Therefore, perhaps easiest if you could give a concrete example of what you’d like to achieve for one of your calendar events, I can then better understand what you are trying to do and how this would work well within Agenda.
I would use the other way around: linking one notes to multiple caldener events. I use Agenda to keep track on which parts of the project I work on which time, so sometimes I don’t get one Agenda Note done and I would like to link this to a further calender entry e.g. on the next day when working on that. But its not super important, but would be a useful feature for me.