Why didn’t Cyberpunk do a beta program and avoid all the bugs?

I suspect it's because they straight-up lied about major features in the game.

Bugs are fixable, but there are major concepts that they advertised (and even showed in demos) that aren't even close to being done.

Even without any bugs, they might've still been sued for misrepresenting the product.

Wouldn't the game leak then? Pretty sure such a popular game had internet betas

Because Betas are embarrassing to management. They want a full game and skip the beta and let the first users beta test the commercial release.

Do you mean an open beta? Pretty sure they had an internal beta, since those are pretty much part of the standard QA workflow.

it could be a marketing tactic, look at how everyone is talking about it