Career era 3.19, on much less rest, ~5400 Inn, ~5700 K, most no-hitters.
It’s definitely arguable —
If he pitched in 4 days’ rest, took days off when he didn’t feel good, etc., his WHIP, ERA, etc might look a lot better. Also, it’s tougher to play for losing teams and Angels and Astros were not great defensive teams.
But it depends how much you value innings eating and longevity. He was between great and elite for 24 years. That’s peerless. But maybe wasn’t as dominant as Koufax or Gibson over any given 5 or 10 year stretch.