Hello — I just made an example of something that might help out. This uses no events just a little effects trickery. You can adjust the blur with the intensity settings or just change the opacity on the BlurredEdge sprite. I just used a rectangle for this, but you can use any shape just make the color white or the divide effect gets weird. Also make sure the BlurredEdge is in front of all other elements. Hope this helps.
**More Info** If you want the Blur to stay in the viewport and follow a player that can be done too. Let me know if you would like help doing something like that.
https://filetransfer.io/data-package/2BHrIBHE#link