Unable to add a new user profile to Apple TV+ through the app

All ‘profiles’ are handled by separate Apple ID accounts.

• The iPhone is a personal device, and I could see why it is intended to have one Apple ID account (user profile).
• The Mac allows for multiple users for login, but can be used as associated device for one Apple ID account only. I haven’t seen attempts on how that goes with Apple TV+. Not certain if Apple TV+ clashes with associated device mismatch.
• Third party streaming devices allow for multiple accounts: Add additional Apple ID accounts - Apple Support. Not certain if that allows accounts that are not included in Family Sharing.

Family Sharing allows access to the subscription for multiple users (Apple ID accounts), where each users will have its own profile automatically, by forming a group of Apple ID accounts.