Those stats include stablecoins!
Stablecoins make up 320 billion out of the 2.3 trillion total market cap, that's why the exagerated drop for Bitcoin.
For example, in the last 30 days, USDT went from 7.27% to 8.12%, there you have it, nearly one full percent of the 60.36>57.97 , 2.39% drop in Bitcoin dominance.
Throw in USDC and others, and the change becomes statistical noise.
You are right but the unstable coins really make the fall in the dominance of bitcoin but it was a little fall. If you look for the coin called hype which belong to Hyperliquid, it increased significantly from $21 to $74. You can also look for coins like near protocol, ondo, ton and many other coins, they increased significantly almost or more than 2 times.