Based on these test shots, the OnePlus 7 Pro has the better cameras.
With that said, I was extremely happy with the Galaxy S10's photos when it was my primary smartphone for a few weeks. During that time, I never looked at a photo and told myself that it was "too blue," or that colors were too saturated. I truly didn't have any complaints.
That's to say that you'd be happy with photos from either phone.
But, after comparing photos from both phones side by side, if a friend asked me which phone takes the better photos, I'd tell them the OnePlus 7 Pro.