What would be the correct way to implement this?

I tried implementing it myself but I have a few problems.

For example, I don't know at what point I must detect that my attribute is a composite/component.

I can detect it in AnnotationBinder by checking if a @Convert is present on the attribute with an AttributeConverter class which has an @Embeddable column type... but what if the @Converter is auto-applied and declared somewhere else?

So I thought it was maybe better to let that attribute be a SimpleValue and adapt its type and columns in the second pass.
But what if there are @AttributeOverrides on the field (to customize columns names)? The second pass seems too late to process those annotations.

If some developer has a bit of time to think about it and explain how it could be done, that would be great.

I really think that composite types are a bit underpowered in jpa/hibernate and I would really like them to be reworked.
( HHH-11812 Open could be helpful too.)

Thanks.