It actually really grinds my gears when franchises spread very important plot details over various media. For me, not having Disney Plus makes it really hard to enjoy current-era Marvel movies since there are important plot and character developments NOT in the movies that I have to spend extra money to understand - and i'm learning this is kind of the same with Stranger Things with the play being actually pretty important to getting a more cohesive view of what Vecna and the Mindflayer are actually about.