If you will take a look at this RSS feed for instance -> https://weblog.rubyonrails.org/feed/atom.xml you can see that it has <content> and <author> fields which are pretty much standard for any Atom RSS feed today. Currently Microsoft Flow can grab the following:
Categories - Item
Feed copyright information
Feed published on
Feed updated on
links - Item
Primary feed link
Represents a wrapper object for batch trigger response
Represents an RSS feed item
Yet two very important ones are missing! Feed author and Feed content!
I recommend to take a look at how Zapier (https://zapier.com) implemented thier RSS grabber to get the right inspiration!