Two years ago we replaced 3 of our blinds that were dog-damaged from this place: https://www.justblinds.com/
We found an exact fit, and great color match. Their recent website makes choosing a color more difficult, and they no longer offer the "economy" line which were a virtual duplicate of the camper originals. Nevertheless, they are a good company, and will work with you, and send you color samples, too. The blinds come out of their clips easily with a release lever.
Getting to the brackets meant I had to REMOVE the valences which were screwed into place on the wall with L-brackets. The only way was to remove the screws with a square-bit driver, reaching upward to the underneath side of the valence top. Not handy removing, and more of a devil to reinstall!