snip

*Feel* where the barbs are, around the perimeter, with judicious prying,
etc, and then *feel* how to release them. If you can't do that, you're
not an engineer, you're just another pencil-pushing number cruncher.

I wish we were in the same area. Maybe you could use that pencil to
*judiciously* release the barbs.

Hell, you've got the exploded diagram of the thing right in front of you.

Maybe an explosive would work to remove the cover on the actual mower.