Computer Configuration > Administrative Templates > Microsoft Edge - Default Settings (users can override) > Startup, home page and new tab page
Both
HKLM\Software\Policies\Microsoft\Edge\Recommended
Specify a list of websites to open automatically when the browser starts. If you don't configure this policy, no site is opened on startup. This policy only works if you also set the 'RestoreOnStartup' (Action to take on Microsoft Edge startup) policy to 'Open a list of URLs' (4). This policy is available only on Windows instances that are joined to a Microsoft Active Directory domain, joined to Microsoft Azure Active Directory` or instances that enrolled for device management. Example value: https://contoso.com https://www.fabrikam.com