From what I've seen, there's indeed very little consistency in titles, if any. As you mentioned, a few places consider senior to be higher than staff, some have a distinction between senior (SWE), staff and senior staff, and some don't have staff level at all. Even among those companies that do have staff level following Google's hierarchy model (this seems the closest to a norm if there's even such a thing), the actual cross-company "value" of that title might only equate a L5. Then you get random weird outliers like Uber's L5B level, which, for all intents and purposes is a "staff" level (in terms of responsibilities and comp) except the title itself.