It seems Elementor puts a suffix on the image depending on the image size selected.
https://app.usebubbles.com/5jBMcwehyyz7234ZeDQn8J/comments-on-wordpress-245642-1584517-cloudwaysapps-com/

Although, this still does not give any insight into why the images placed through the Xtemos Category Block are slightly blurry when compared to the elementor images.