This is the macOS version of https://bugs.webkit.org/show_bug.cgi?id=259156, which was filed to be iOS specific.
Using macOS Venture 13.4 and Safari 16.5 with VoiceOver on a site that uses aria-description (Example: https://a11ysupport.io/tests/html/aria/aria-description.html) results in the description not getting read out. For the text field, "more content available" is read out rather than the description. The text content doesn't read the description, nor does it provide context that there is a description.
I would expect that aria-description would have the same readout behavior as aria-describedby, in a similar way that aria-label has the same readout behavior as aria-labelledby.