Apple TV app forcing me to buy channels when I already subscribe to the apps

Why is Apple TV app not allowing me to watch up next episodes to shows on streaming services I already subscribe to such as Showtime, Paramount +, AMC +, & other apps?

I'm subscribed to these streaming services through their respective apps so it makes no sense why Apple won't allow me to use Apple TV app to access my content. Apple connects for most apps but not Showtime, AMC +, & sometimes Paramount +. Apple is trying to force me to subscribe to the channels through the Apple TV app in order to watch shows on the apps that I already subscribe to. I'm not going to double subscribe & I'm not going to end my subscriptions through the apps just to start a new subscription through Apple. I'll just stop using/paying for the Apple TV app unless this is fixed.

If I can't use the Apple TV app as a hub for all my streaming services then there is no reason for me to use the app... The entire benefit of Apple TV app is using it as a hub for all your streaming subscriptions so the up next tab shows you your new weekly episodes when they come out. Otherwise the app is pointless because Apple TV plus doesn't have great content.