No, it's not irrefutable.We've had a fair few photos, multiple being irrefutable, and all emerging after years of expectation and rumours and all with the usual suspects saying "this is it".
I don't see why there would be any doubt about its existence.
Pictures at SAC have always been harder to come by and less consistent than CAC (think about getting FC-31V1 and FC-31V2 photos taken at SAC and how infrequent it was, or even Flankers) and with the overall greater security sensitivity, this should be expected too.
For the next few years I think we will be lucky to get a couple of pictures per year of it, taken from the ground.
In other words, the pictures we've been getting of it and the frequency and quality of it, is entirely normal and expected for SAC and for the current strategic environment.
11 years ago when J-20 first show up, the fans took high-res photos like this:
How can they take photos like this in 2021?