There are a few things worth understanding.
If someone wants to work at a startup, Google isn't really going to compete for your offer
But if you're going to big tech cos you can get them to compete with each other.
Know your audience: say, I'm really excited about the potential of working with you, however I have a few other interviews with comparable public tech companies
I'm not ready to make a decision because I want to see that process through, although there exists a number you could tell me that would get me to stop looking immediately.
This will probably give you a worse number than you'll get if you actually get the additional offers, but if you don't have them it's a truthful way to indicate they're not quite hitting the mark
Sure maybe offer is a bit too far, idk. Definitely no way for them to check though. And in all other ways the game is rigged because employer usually has more information than you.