If you configure the preceding policies and this policy, all browsing data is deleted when Microsoft Edge closes, regardless of how you configured 'AllowDeletingBrowserHistory' or 'ClearCachedImagesAndFilesOnExit'. If you enable this policy, don't configure the 'AllowDeletingBrowserHistory' (Enable deleting browser and download history) or the 'ClearCachedImagesAndFilesOnExit' (Clear cached images and files when Microsoft Edge closes) policy, because they all deal with deleting browsing data.

If you disable or don't configure this policy, users can configure the Clear browsing data option in Settings.

Note that if you enable this policy, it takes precedence over how you configured 'DefaultCookiesSetting' (Configure cookies) If you enable this policy, all browsing data is deleted each time Microsoft Edge closes. Browsing data includes information entered in forms, passwords, and even the websites visited. Microsoft Edge doesn't clear the browsing data by default when it closes. Clear browsing data when Microsoft Edge closes

How to clear cache on edge browser