Computer Configuration > Administrative Templates > Microsoft Edge > Startup, home page and new tab page
Both
HKLM\Software\Policies\Microsoft\Edge
By default, the App Launcher is shown every time a user opens a new tab page. If you enable or don't configure this policy, there is no change on the Microsoft Edge new tab page and App Launcher is there for users. If you disable this policy, App Launcher doesn't appear and users won't be able to launch M365 apps from Microsoft Edge new tab page via the App Launcher.