While I completely disagree with your characterization of chess as a "solved" game, whether it's solved or not also doesn't really matter. Aimbots can crush CSGO pros, and OpenAI beat TI winners OG in 2019, but at the end of the day the strength of computers is irrelevant because we want to watch sports being played between humans, the strength of algorithms or computers (mostly) doesn't play into our enjoyment so long as the game remains complex for the human players and spectators.

As for meta changes and new patches, chess kinda sees this in the rise and fall of certain openings. For example, the popularity of the London System in the recent decade and the development of new theory within popular openings (I recall the Tal Variation of the Advanced Caro-Kann being popular in a recent tournament even though the Short variation was seen as the most critical way to continue for white for a long time). And this is just at the highest level, anyone in online blitz has had to learn to refute the Stafford Gambit because it "entered the meta" after Eric Rosen popularized it a few months ago.

I disagree. Meta updates take away from the enjoyment for me.

Id much rather watch competitors competing on 100% equal terms, without any developed advantage other than one created through the competitors skill.

Rocket league is a fantastic esport, and it’s been the same mechanics for years. There are no ‘special items’ or OP’d power ups. Both sides are 100% equal. It’s why I love it, the game is pure - Competitor vs competitor.

Chess is "solved by computers" today, as in they will outplay the best humans, but that's in part because chess provides you with perfect information about the enemy's position at all time.

Most (all?) esport games use fog-of-war (RTS) or level design (FPS) or some other mechanism that hides the enemy from you. Without that, esports games have also been "solved by computers" for decades.

There is of course a chess variant with fog-of-war (dark chess). As far as I know, computers don't beat humans at that.

Some of the best esports with the deepest meta have no/little patch updates and their meta is constantly evolving. It’s the same in chess too. If anything, continuous patch updates that change the meta are a sign of weak game design.

Chess does have meta changes, though. Especially as chess engines become more advanced, like with the release of AlphaZero, different strategies have become popularized as a result