Change subscription from one of my Apple accounts to another of my Apple accounts.

There has never been a way to transfer subscriptions from one account to another, although you can contact Apple directly for confirmation.

Contact Apple Support - Apple Support

There's this --> Migrate purchases from one Apple Account to another Apple Account - Apple Support

It doesn't make any mention of subscriptions though, either as something you can do or cannot do. You may wish to follow the advice in a previous post to clarify that with Apple. Also note all the limitations.