Try pushing down on the cap while wiggling the key. Helps release the pressure on the latch.
I'd keep working at it JIC, I've had mine hang up after a week or so, but it luckily ended up working after some fiddling.
Removing the allen screws ALMOST gets you there, there is a phillips head screw UNDER the cap that also needs to come out. If you cant open the cap,,,,,not able to get to that screw.
Not sure about removing the lock cylinder, you would need something to move the latch.
I do believe there is a screw on cap kit available for other Kawis that would fit on our bike, maybe an option?