If you ask me, every phone of a generation has pretty much the same quality. But that's my thought on the matter, I might overlook small pixels of details, but yeah, I dont take a lot of pictures. I can only tell the difference when I take a picture on a newly bought smartphone and then remember the bad quality from the pictures on my old phone.
If it's true that Oppo does take better selfies, then I know which brand of phones I don't need to consider, as I care more for battery, memory space, and most importantly, RAM. I could consider Oppo if those specs are good and the price is reasonable.