After analyzing hundreds of forum posts, security reports, and firsthand attempts, the conclusion is clear:

Apple aggressively cracks down on enterprise certificates used to distribute pirated apps. You might install a "working" Netflix IPA, but within 24 to 48 hours, the certificate will be revoked. The app will crash instantly on launch. You lose all your downloaded content.

: Sign in to your Apple ID on a modern iPhone or iPad that supports the current Netflix app. Download Netflix