As of writing this comment, Claude Opus 5 has an intelligence score of 63, not 59 (it's not the same as Gemini 3.8 Flash).
With a score of 59, Gemini 3.8 Flash is in eighth place, falling behind even Grok 4.6, Kimi k3, and GLM 5.3.
They said Opus 5 medium - which does have an intelligence score of 59 (you have to select it manually from the dropdown to see it)
That 63 score is for Max. The OP specified medium.
They are all much larger and more expensive models. Google does not have a frontier model right now, but for cheap ones, they are better than event the chinese models now.