It's an open secret in the high performance computing world that China achieved exaflop performance sometime last year but chose to keep it under the radar to avoid scrutiny from US tech policy makers and avoid potential tech sanctions that would complicate things.
US actually did sanction them. They sanctioned at least 7 companies that worked on components for those Exascale systems only a month after the systems succeeded in exascale Linpack benchmark. That's even before Nextplatform reported the existence of those systems. Phytium is one of the companies that got sanctioned in that round.
As for that top500 list, some people in HPC community speculate that China may never submit a system to that list in the future. If China totally stops submitting to it, that list will become incorrect and irrelevant over time.