There’s already an existing suggestion discussing options to filter the watchlist for content available on certain channels or shared libraries. I suggest you comment/vote in that thread in order to help us avoid distracting or cannibalizing votes. Unless I’m missing some unique aspect of your suggestion I’ll close this thread as a duplicate.
Actually I want the opposite, not filtering what I can’t watch (" Not Available on Your Services/Plex") but what I can watch. But I will use that thread fir the suggestion. Thank you