I don’t quite understand what you try to do. A pickup where after overlap the mesh is hidden, and a text is displayed can also be archived with a textRender Compontent inside the pickup actor bp. You can go the way with a widget, so you can create a UMG with a variable exposed (like timerSeconds : int) or better a function to trigger it. Then on overlap in the pickupActor hide the mesh, and set the nodes like in the screenshot to fire up the widget timer. I personally would go with a text render if you really only want to display text timer.
if you want access to the pickupActor from within umg, just create an actorRef (or pickupActorRef) Variable in the umg and set it like above from within the pickupActor to “Self”