How do I prevent my content's title from appearing in the  tag of my RSS feed?
I haven't tried to reproduce this on my end, but I found a Drupal.org thread with advice that may be relevant:

https://www.drupal.org/project/drupal/issues/2946812#comment-12501714


  using 'Show: content' looks like a bad idea to begin with.
  
  I can get some nice clean output:
  
  
  Choose 'Show: Fields' (so not 'Force using fields', just plain fields output)
  Close the dialog without setting the required fields (just click the X in the top right corner)
  Add some fields (title, body, a url, node id)
  Go to Row style options (so click on the 'Settings' link behind 'Show: Fields'
  Fill out the required fields with the fields you've added
  Add more fields if you need them to fill out the required settings
  


If you build the description this way, you should easily be able to omit the title field. Good luck!