If anybody is interested, I have converted all the cycling .FIT files from the Workout library into the .MRC file format (I needed that to upload them to Rouvy)
Here is the link to download a .ZIP file containing all the .MRC files https://drive.google.com/file/d/1oOYrJvQo9ubWY6eMJzScXYcuqY_CEh-V/view?usp=share_link
Hoping it helps