I think if I had to do something today.... I'd...
Cut off the existing cable step mounting boss to make the bottom of the box completely flush.
Then hang one of these underneath (I would probably shorten the drop-down a bit though)
View attachment 883035
Then I'd mount one of these on the top of the box lid for better traction, plus it would match the new hanging step....
View attachment 883037
This wouldn't solve any of my other problems, ie making it more like stairs than a ladder, or making the first step height lower, or decreasing the distance between the first and second step point... But, it's super functional, safer, won't fail to deploy and doable without much engineering.