Lack of MDFs does not mean that you can't fly missions. It's an intelligence product that assists with mission planning. That's like saying your car is completely unusable if the builtin maps are a few years out of date.
Ukranian hackers know how to hack John Deere tractors.. hah, downloading files from a Ukranian web forum to install on your F-35 would be very dystopian cyberpunk.
We've made great strides in reliability over the years, but planes are anything but solid-state like integrated CPUs are.