After an update to CE2.4.5 my mobile menu is not working on luma theme. It's allready discussed on stackexchange, but there is no working solution. Problem is that subnav is not opening (example www.mallorca-fanshop.de).
Start by clearing your Magento cache to ensure that any outdated or conflicting files are removed. You can do this by navigating to System > Cache Management in the Magento admin panel and clicking on the "Flush Magento Cache" button.
If you've made any customizations to the Luma theme files, try reverting those changes temporarily to see if the issue is resolved. Sometimes, conflicts or errors in custom code can cause problems with the mobile menu functionality.