Hello Ivan
The "Browse" menu items in the Configuration->Menus section (see screenshot #1) are ALSO necessary for the dropdown menu at the top (see screenshot #2) to function correctly. You cannot delete this entire "Browse" menu definition or this top drop down will not function correctly. Individual items can be removed or added, but not the entire Browse menu.
Did you delete the entire 'Browse' section I've outlined in screenshot #1? If so, you will need to re-add it, and the errors should go away - this will fix the top "Browse" drop down button. I have added screenshots showing how these menu items are configured in a fresh 2.4.x system.
If you want to permanently remove the sidebar items you highlighted in red in your screenshot on the AtoM homepage, it is easiest to customize the theme by removing these lines:
You can make this modification in the file I've shown above, but be aware the when upgrading to the next version of AtoM (e.g. 2.5) you would need to remake this change as it will be overwritten with 2.5 code.
It appears you may have a custom theme in your plugins folder? If this is true, you can override the file apps/qubit/modules/staticpage/templates/homeSuccess.php in your theme folder structure. This is a better place to make this change as you will not have a problem with having to re-make this change when upgrading to 2.5.
Make sure to restart php-fpm service and clear AtoM's cache (php symfony cc) afterwards making code changes. Always a good idea to test changes in a test or demo system first to see how changes affect things before moving to a live system.
Steve