Always mobile menu in desktop view

Same as many others, I’m facing the issue that on my page (https://www.timvandermeulen.de) despite the correct settings, there is always the MOBILE menu showing instead of the desktop one.
I’ve set all the breaking points accordingly.
I’ve tried “Theme Panel > Scripts & Styles, click Save Changes, then clear your cache”.
I’ve restarted. I’ve de-activated and re-activated the theme. It’s hopeless.
Nothing seems to help.
Nobody has a clue. Everybody just keeps posting “Theme Panel > Scripts & Styles, click Save Changes, then clear your cache”.
It’s NOT a cache issue. At least not on my end.

Similar topics marked as ‘resolved’ that haven’t helped:
– https://wordpress.org/support/topic/mobile-menu-always-showing/
– https://wordpress.org/support/topic/mobile-menu-shows-up-in-desktop-view/
– https://wordpress.org/support/topic/mobile-menu-always-showing-2/
– https://wordpress.org/support/topic/mobile-menu-appearing-on-all-screens/
– https://wordpress.org/support/topic/mobile-menu-button-always-shown/

The page I need help with: [log in to see the link]