My goal was to have a bike that will work on the road but stands up to rail trials / gravel roads.
I recently bought a gravel bike. Before buying I knew I did not want a road bike or a mtb, I already have those. Like you, I wanted a bike I could explore on and fill a different riding need.
I chose the Cannondale Topstone carbon. At this price point you can find bikes with just enough rear suspension to take the edge off rough gravel roads and some single track. At the same time the frame and geometry allow you to blast down a gravel road quick and efficiently. It's also lively on the road.
My road bike is faster on the road, my mountain bike is better on trails, what I like about my gravel bike is that I find I'm less concerned about speed and more into connecting places I would not ride on my other bikes. Yes it's a novelty, but for me it feels fresh and keeps me interested in riding.
J at Halters has one of the best inventory of bikes you'll find in NJ these days. Do some research, read reviews, check out some bikes.
Yeah gravel is a trend, but so was cx, xc, 24hr races. It's still fun.