For each Site Access that is loaded, we are in fact loading a Landing Page with loadContent (https://github.com/ezsystems/ezplatform-page-builder/blob/2.3/src/bundle/Menu/EventListener/ConfigureMainMenuListener.php#L87). This causes performance issues as we only want to get the Language for route parameters, and the whole Landing Page content is built which is an overkill.

Having a larger number of Site Accesses and large Landing Page contents will result in performance drops for each time we are loading the Back Office page.