Question 11-Hour Layover in Iceland at Night: What to Do?

Hello all, I'm planning a trip to Iceland (4 days) and Amsterdam (6 days) and we've got an 11-hour layover in Iceland at night. We’ll be landing around 9 PM and our next flight is at 8 AM. I know there are some beautiful sights to see, but is it safe and practical to explore at that hour? Should we head to Reykjavik for some late-night fun, or would it be better to find a cozy spot to rest? Any tips for making the most of this layover would be great!