While Disney had the distribution rights to the film internationally, in North America, the film is technically a Paramount production and so it seems unlikely the film would release on Disney+.
One of the criteria for episodes of Prop Culture is that they had to focus on movies that Dan Lanigan himself was a fan of.
Dragonslayer is even brought up in an episode of the show’s first season as one of the host’s favorite films.
Although, as Lanigan mentions here, that one might be a tough sell.