Samsung has officially confirmed that the Galaxy Note 21 launch is not in question, dismissing earlier rumours about the series' discontinuation in 2021. However, industry insiders are of the impression that there will be only one variant of the phablet this time around.
https://www.notebookcheck.net/The-Samsung-Galaxy-Note-21-launch-has-not-been-cancelled-says-a-company-official.509961.0.html
Even with the Note back at this point a headphone jack would be as much a surprise as any. I probably won't wait till the end of next year anyhow, even ROGP4 should be released earlier.