If it's really at 2022-05-01T16:00+1000, then it doesn't matter what DST policy changes occur.
1/ my birthday party will start when my watch shows this local time and date
2/ my local time and date are dictated by the legislative body responsible for this geographic area.
If it's really at 2022-05-01T16:00+1000, then it doesn't matter what DST policy changes occur.