Not having access to the server is a pain. Really some simple edits to your [Robots.t](https://Robots.tt)xt file and you would be good to go. See if there is another feature in Yoast that will allow you to de-index specific pages. if you want to try a different SEO plugin, I believe Rank Math allows for that.

is there anywhere in the media file that you can select de-index?