I can't imagine there's anything "extraordinary" about Ryanair scheduling a flight too close to the time when ATC closes for the night.

But whether Ryanair will pay out without going to court is another matter.

Did you actually fly the next day and receive "duty of care" from Ryanair? If so, a "refund" isn't going to happen - simply a dispute over compensation (and possibly the refund of hotel costs, etc.)