It is not that confusing. Amazon sells and rents digital videos. Anyone can pay for those and watch them.
They also have prime video, which is a subscription service that is included with an Amazon Prime subscription (although you can also pay for it separately if you don’t want the other prime benefits)
With prime video, you can watch all of the Amazon originals (like the expanse season 4), and a subset of their entire collection that they license from other publishers.
You can filter to just display shows and movies that are included in the prime subscription, so you don’t keep picking a movie or show and find out that it is not a part of prime.
They also have prime video, which is a subscription service that is included with an Amazon Prime subscription (although you can also pay for it separately if you don’t want the other prime benefits)
With prime video, you can watch all of the Amazon originals (like the expanse season 4), and a subset of their entire collection that they license from other publishers.
You can filter to just display shows and movies that are included in the prime subscription, so you don’t keep picking a movie or show and find out that it is not a part of prime.