Took a chance on a bed extender meant for the another pickup truck and it fits and looks way better in my opinion than the ford one.

Link to Bed Extender:
https://a.co/d/5KBGkGo

Link to Cubby Grid for Maverick:
   • Ford Maverick - Easily Mount Your Pho...  

Measurements I took to ensure fitment.

Width at mounting points:48 3/4”
Height Max to clear cover: 20”
Mounting point to wheel arch: 18”
Mounting point to edge of tailgate: 26”