I think the first thing you have to realize is that the rules around the Force are constantly evolving (and always have) and that how much training one needs before they’re a “Jedi” is really anyone’s guess.

But, beyond that, I don’t think I’d say at all that either has mastered the Force. And I think we put too much stock into the idea that you need a teacher to be trained, and I think that’s the point here. A teacher is helpful, up to a certain point. Rey doesn’t need Luke (or his bloodline). Kylo doesn’t need Snoke (or his backstory). They can forge their own paths. This is their story and their future.

Why do I have to realize? All the films leading up to TFA shows Force users need a significant amount of training to master the Force. Even in TFA Snoke suggests Kylo needs more training. I think future directors should respect the in-universe rules, and when they don’t, provide explanations. I’m not fond of a universe rife with inconsistencies.