The webform builder is not working

Have you done a backup then tried repairing the module configuration? You repair the configuration at /admin/structure/webform/config/advanced.

@cilefen Just tried that. Logged out and in again, and it's the same. no drag-drop

Are the "source" and "elements" task tabs visible at the top of the page? What are the URL paths involved? Can we get more complete screen shots that include more of the page, in particular the top?

Ofcourse, heres a more complete screenshot https://share.cleanshot.com/wKz9FMCs

The webform_ui module is most likely not enabled on your webserver.

Yes it is indeed enabled on the webserver.