You can be at either end of the parameters with the same bullet and gun.
For instance a 50gr V-max out of my .223 will make a lovely red mist out of a p-dog at 75yds (or severely mangle a fox), but will usually drop a coyote DRT with no exit.
At 200 + yds the same bullet has lost enough steam that complete fragmentation is getting iffy, and will result in some coyotes running (but might be great on a fox).
As with all things ballistic it's a trade off.
A frangible at it's best is far superior to a traditional hunting bullet at it's best.
The frangible is prone to failure when too fast or too slow (to close or far), and depending on the mass (and density) of the target.
The traditional hunting bullet, will be near it's best from the muzzle out as far as you can shoot on any sized game.
I doubt you'll find a round that will be consistently fur friendly for fox out of a .223 if you're looking for no exit wound. It's going to be hard to keep a .223 bullet of any type inside an animal as small as a fox.
The frangibles when they exit can be pretty messy, but even a more substantial bullet will probably leave at least a caliber hole out, needing to be sewn.
Some guys have reported pretty good success on fox with a 17 Rem.