You can create a Hide My Email address manually if you go to System Preferences > Apple ID > Hide My Email (Options) > Tap the + button.

Feel free to use a one-off email account (as long as you have access to it indefinitely, since it ties your devices together). Unlike Figma, Notion, etc we don't ask for anything other than an email.

We tried implementing Apple sign-in but found the experience pretty weak, both for the end user and for us on the business side.

In the future would like to implement some kind of disconnected mode to remove this friction. But email is needed for the sync aspect, which is one of the biggest selling points (and wow moments) of the product.