Update:There are now some helpful videos and an easy wizard that helps you do this.
Pop-up Build Wizard: https://www.youtube.com/watch?v=U6FoYdzJwZ0
Video course on creating a pop-up video:https://academy.ajarproductions.com/p/create-a-video-pop-up-basic
Yes, create your own popup with a MultiState Object (MSO).
Create a "blank" state with an empty rectangle as the default state.
Create a button with a Go to State action and a video play action.
Inside the MSO's video state, create a close button that stops the video and returns the MSO to the "empty" state.
The popup MSO can cover the entire screen, in which case it will block clicks behind the popup content (like you might expect).
More on MSOs;http://ajarproductions.com/in5course/?lesson=msos