I've been informally told by a KDE developer that X11 multi-DPI isn't a feature supported by KDE, so 5.27 breaking something they don't support is not a bug. See https://pointieststick.com/2023/02/24/this-week-in-kde-even-better-multi-monitor/comment-page-1/#comment-34938 Unless this is also occurring for non-multi-DPI users, it can be closed as resolved.