Apple TV+ Casting protected movies

Hi I have an Apple iPad mini and absolutely love it. My previous tablet was a Samsung Galaxy s3 but it didn’t have the size and performance of the mini. Anyway with the mini came a free Apple TV+ subscription for 12 months. Great I thought so I signed up to see if it is worth the $8 a month. Started off ok some nice programs to watch however call me old school but I don’t watch content on my mini. I want to watch it on my TV. Hang in there the question is coming. I have a google Chromecast which as most of you would know allows me to cast google and android devices to my tv. It also casts my iPad mini to my tv however when you want to watch a movie on your tv with your device it spits out a stupid error about not allowing the protected movie to be displayed on my tv. Apparently I need To buy an Apple TV device. Why? I already own the iPad and the rights to watch the media, why make me fork out more money just to be able to watch the media on a large TV. If I have this all wrong then I apologise and then perhaps a talented Apple user can advise me how to cast my iPad mini Apple TV+ Protected media to my chrome cast TV.

thank you