5 orcs is doable but difficult, even if its the first mission. 10 raiders sounds a bit much. Was it a 3-skull contract?
Anyways, game is randomly generated. If you try again you will get different missions and maybe do better.
I don’t think Veteran is too hard, in my experience it’s just slightly bigger enemy troops. By the way, you could have run into 5 orcs on beginner just as well. Maybe it would have been 4 instead.