It shouldn't be a question, nobody is going to have a stealthy jet not able to stealthily communicating with each other. Besides, China is as good as US, if not better than US in the related area, such as phased array anntena or beam forming digital processing. China is the first country to field full digital AESA AWAC and Huawei is the leader of 5G (digtial beam forming), that is the industrial fundation.Does J20 have advanced datalink like F35?
When one fighter jet spotted something, it will be shared with every other platform.
Military technology is some times misunderstood to be super-duper, but very often it is just re-inforced civilian tech. The two are of the same technology level with different emphasises developed by people with same education.