limiting access to Apple TV on family sharing?

I want to provide educational videos to patients on an ipad using Guided Access. I've uploaded some videos into the library on Apple TV after linking this particular ipad to my main apple account. ( I had to create a new Apple account for this purpose, in order to eliminate the security risks of handing an ipad logged into my main Apple account to a stranger.) So, I have the extra ipad logged in as a family share member, which won't allow a user access to any secured info on the main account.

However, when using guided access to show them the videos I would like them to watch, they are still free to view other movies and videos within Apple TV if they poke around on their own after viewing the video. I suppose I could unlink the ipad from the family sharing, but then I lose access to the other software I have already purchased and may want to be able to use on the extra ipad, including some articles, books and documentation.

I'm looking for a way to unlink Apple TV access to the extra ipad while still having access to my main shared account. That way, I can control what the viewer sees with Guided Access and keep them from using the ipad in other ways. I'm not sure this is possible, as it seems one either has family sharing access or not, and that it can't be customized, except for perhaps some child control settings, which I've not fully investigated.

Any ideas about this? Thanks.