Sydney Main Menu: How to remove Dropdown Icon

I have several Websites on air with the Sydney theme. Since I started a new project with version 6.0.2 the main menu appears, in case of submenu-items are present, automaticaly with a dropdown symbol on pc screens (before they only appaered on the mobile versions, which is ok).

To reduce the space used for the main menu, I prefer to remove these dropdown icons. On this forum I discovered a css code to remove them, but the problem was that they did not appaer anymore on mobile screens too. And it was not possible to fold out the submenusat all…

I did remove the maximum plugins. The only plugins that still are on the WP Installation are…
Active Plugins: Classic Editor, Loginizer, Page builder by Site Origin, Site Origin WidgetsBundle, WP super Cache, Yoast SEO.

Deactivated plugin: Akismet Anti-Spam, , Sydney toolbox

Can someone help me with the specific code for removing these icons only for pc screens?

Thanks ahead!

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