Steps to reproduce the issue

Create an article. Set the start date to now, set the created date to something in the past. Save the article.

Expected result

The start date should be in the pubDate field of the rss feed.

Actual result

The created date is in the rss

System information (as much as possible)

Joomla 4.3.2

Additional comments

The startdate is the actual date on which an article is published / visible on the site. Feed readers look at the pubDate to determine the published date. If you plan an article days or weeks in advance and create and publish other articles after this article, the feed reader won't pick up the initial article, since it thinks it's older than the other articles, even though the sort order in the feed is correct (by published up date).