Here’s something to think about: Odo is self-taught.

No mentor. No tracks to follow. Just plunked into an office by himself on a chaotic station. And he went, in a matter of years, from ‘guy randomly assigned to investigate a murder who borks it up’ to 'single-handed enforcer of justice with a network of contacts that stretches from Starfleet to Cardassia Prime’.

He doesn’t just keep a lid on station shenanigans. He interrupts smuggling rings that are entirely off station. His tendrils are everywhere. And he’s always watching.

And this is our Odo. Who means well.

I can very easily see how the Dominion came to be.