Regarding the orm.xml format, we have previously had a detailed discussion about it in this thread -
Wherein you have mentioned about the transformer tool but since its not completely ready as suggested by you, we have not gone for this right now. Will probably use it when we decide to move to future versions of Hibernate. Till then, since the hbm.xml files still work with hibernate 6, we would like to go ahead with them also keeping in mind the timelines of our release as well.
However that being said, this will still not solve the Tuplizer issue that we are facing. So if you have any workaround for that, it would be much appreciated.