@ascentale a2. I love my Son dynamo hub and light but don’t think it’s bright enough for gravel riding. I’d make sure whatever you get is bright enough and durable enough for gravel.
I found Joe Bike in Portland very helpful: https://www.joe-bike.com/product-list/accessories-1109/dynamo-hubs-lights-1263/

@DurableAce @bikenite