The joint Australian and New Zealand national committee on Records and Document Management Systems recommendation to both Standards Australia and Standards New Zealand to adopt PDF/A-4 was completed on 23 December 2022.
Adobe engineers have formally added support for Unicode 15 to the CMap resources for both Adobe-Japan1-7 and Adobe-KR-9 in the Adobe CMap Resources GitHub repository.
This freely-available PDF file includes 8 test cases that only render correctly if the abbreviated key name is used. If the full key name is used then something else happens (precisely what is implementation dependent!).