If you can find the tufo gravel thundero, those might fit what you want. I’m not sold that the center tread would do anything for traction, but they seem to be awesome for durability. They also roll quite fast. Additionally, I’ve had great luck with the specialized Pathfinders. One of my friends was on the podium at migration gravel, he ran the s-works pathfinder and had no flats, the pathfinder pro is supposedly even more durable. They both run pretty fast as well. I’ve used the s-works pathfinder and the tufo thundero and felt grip on both was awesome.
Seems like almost everybody around here has the Pathfinders.
So, clearly they work decently.
I really like the Terra Speed (in 40c) -
But as a R tire.
It was OK up front, but I prefer a bit more grip
& cornering knobs up there, and am willing to trade a little RR to get it.
So - I went back to my mtb xc racing roots, and have been running a “mullet” for the past 2+ years, to good effect.
F - Spesh Rhombus Pro 42c - looks like a mini mtb xc tire!
R - Conti Terra Speed 40c. - held up longer than expected, finally got the hint to replace the last one after a dozen + weep spots appeared along the centerline of the entire tire. 
And as I learned mtb racing - low RR isn’t the limiter on overall speed;
being able to corner and brake where and when you want/need to is.
YMMV.
I never understood the slick middle/knobby side design. It looks cool but makes less sense the more you think about it.
The knobs are far enough off to the side that the only time they really engage is at fairly steep lean angles unlikely to be hit in any conditions requiring such aggressive tires. The only time you’d actually lean that much is on the road or very smooth dirt, where knobbies have less grip than slicks. Seems almost like there should be knobs in the middle and slicks on the sides, but that wouldn’t really work unless the rubber was super thick.
Maybe I’m missing something, I don’t do much off-road riding.