Apple ID replaced with a new one. What about the purchase?

Just for my curiosity and knowledge, I do understand that content purchase with an Apple ID, are only available to be re-download only with that specific Apple ID.

If for any reason I update my Apple ID, I do not create a new one, but just update (edit)(replace) with a different Apple ID, are the purchase still attached to the old one or are 100% available with the new Apple ID that I just replaced?

Thank you so much and have a wonderful day.