Synchronize the properties of AD users with the Sharepoint Online list

I'm trying to create an employee directory on an online SharePoint list from the properties of our local AD users. I have created the list on SharePoint with the properties (Full Name, Email, Mobile Phone and Business Phone). I've also installed Microsoft's on-premises gateway on a local server and checked it on powerapps.

What could I use to get local AD user data from the SharePoint online list?