Is this an impossible compromise?
No, I don’t think so. I have a Bianchi Mutt “do-it-all” bike. Even with rigid forks it always surprises me how good an “all round” bike it is. It is nice and light and a good pedaller so even with 2.1 knobblies on it is a pleasure to ride on road, but off-road it is very confidence inspiring. Ok, so it’s not rock-muncher, but I have a “big bike” for that. It’ll get down without being too nervy, I just can’t go at it like Steve Peat.
When I bought it it was very much a “euro style” XC bike, with narrow flat bars and a long stem. It was naff to be honest. Wider bars and a shorter stem have made it a brilliant do-it-all. I know this is hardly recommending you a frame, but just an assurance that you can get what you want 😀