The key is that you need to work with the repeat item as a dictionary. The dictionary you defined contains dictionaries. When you take an entry from the dictionary, you need to treat it (the repeat item) as a dictionary to access its properties.
To make it viable for me to work with I added a text entry at the start with the content of the comment and swapped out the shortcut input reference to be that text instead. I also swapped the mail action to be a quick look.
Here’s my modification to what you posted based on the above notes.
https://www.icloud.com/shortcuts/8a57930416be46c79d756827d27963bd
Hope that helps.