I haven't gotten a response from Apple Support yet, but I figured I´d test a cancel and re-submit, and this time it worked! App is finally in "Waiting for review". Hurray!

@fredy21 great to hear that you got it sorted :) Did it go into review without you doing anything? Or did you try to cancel/resubmit and then it went through?

Still the same status for me as well. My support ticket was created on January 26, still no solution.

One thing I did differently when this issue started was that I added a semi-large attachment to App Review (a mp4 video explaining some stuff). I´ve been wondering if this could have been what's blocking the process. Other than that I just did what I normally do when submitting updates, could be just a random incident also I guess. I´ve since removed the attachment again, but that did not help. I´ll keep you posted on any progress on the issue.