From these charts that that just isn't very convincing anymore:
https://socialblade.com/twitch/user/gmhikaru/monthly
https://socialblade.com/twitch/user/chessbrah/monthly
And I say that as someone who was watching Hiarku on twitch in 2018 and even wrote long post on this site about why Chess is the fastest growing esport" in 2019. [ I seem to have lost which account I posted that under however, I maintain separate work accounts and suspect I posted that one one company time (oops!) ]
But looking back, I was over-optimistic, not about Chess' prospects as an esport, but about how much it had really grown given what happened when we saw a real boom from the pandemic, from xQc and pogchamps, and from the Queen's Gambit.