Unfortunately not at the moment. The underlying Qt framework is quite restrictive in terms of the options for window z-ordering. I think there is the ability to make something topmost, but I seem to recall that it can cause other undesirable behaviour (I can’t remember what, alas, but I do remember getting quite frustrated with the limitations)
AutoHotkey works well enough (see link plus instructions above, and this is for Windows). After all’s installed - which shouldn’t take more than 2 minutes - you can force the video window on top with CTRL - spacebar. It then is on top of everything - Dorico, windows explorer, any internet browser, etc. If that bothers you you can drag the video window to a second screen, or click on the video window and hit CTRL - spacebar again.