Yes, if they throated for longer heavier factory loads, that’s a huge point. If Hornady is smart, they will be loading their heavier yell, the bullets into the ARC.
The throat dimensions of the Valkyrie don’t allow for loading out longer bullets Without pushing it deeper into the case then is ideal. I think that could be the biggest difference and is what would allow a bigger velocity difference.
Plus there are already bolt guns with the Grendel/ARC bolt face. And, there is the availability of good Grandel brass.
For AR platform, not as much difference IMO.
I think the velocity game is a little bit higher than that. But, I can’t remember from when I was comparing the Valkyrie and 22 Grendel.