How to fix unresponsive open and save dialogs in macOS Sonoma

Hi Apple Community,

after upgrading to macos Sonoma open and save dialoges in any apps remain beachballing unresponsive for seconds. While waiting Activity Monitor shows "Open and Save Panel Service" with high cpu. Finally I can choose files or save as expected. This affects all user accounts. But it does not happen when booted in safe mode.

I'd be happy about any support or hint to solve this issue.

Thanks in advance!

[Re-Titled by Moderator]