I’ve struggled with this as well. Best solution I’ve found so far is to pass these kinds of function requests thru the player controller. This is because the widget is owned by the player controller so its easy to talk that way, and you can get to the player controller from the level blueprint too.
I think the issue is that on the one hand, the level blueprint cant bind to a specific widget because it doesn’t really ‘exist’ until created during run time. And on the other hand, widgets could be used on any map and as far as I can tell there’s no way to call up the current level in BP. Maybe I’m making all this up. But give what I said above a shot, bind a function in the level blueprint to the PC … then call that interim event on the PC that owns the widget.