All of the bikes you mention are awesome, but I think you are right, in that you can probably get a road bike with 25 cm tires and be fine on packed dirt. I have the Silque (albeit, a carbon one) and I have no problem on smoother packed dirt. I am about half an inch taller than you and a couple of pounds heavier, and the Silque is the best fitting bike I've owned. I am on a 47 cm Silque, and I switched out the Trek bars for the Specialized short and shallow ones I've used for years. Specialized's sizing is different and I am pretty sure I would need a 44 cm Ruby. My friend, who is about 5' 2" has the 48 cm Ruby and it seems big to me.
I gave up trying to find a gravel or cyclocross bike. There's a few new ones for women that are in smaller sizes, but the geometry still comes out wrong for me. And, for a 3d bike, I am not going to spend 4K.