Hi and welcome to the forum:
That setting pretty well fixes JPG files in that mode. If you have access to post production software like Photoshop or Lightroom, you MIGHT be able to recover some of the image contrast.
I would strongly recommend also saving your images in RAW as well as JPG (if the latter is what you normally use). RAW files are not impacted by things like watercolor mode, and they allow far more modification to the images in post production. Even if you can't use them now, in years to come, when you become more proficient, you will find you can go back and some serious tweaking to your stored RAW files.
JPG and RAW are file formats that you select in camera. Look on the first page of the Red menu. If in doubt, consult your manual.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.