AFAIK there isn't data about fatality rate for rideshare services (I'm sure Uber has this data but I don't think they make it public). Without this data I wouldn't automatically jump to the conclusion that rideshare services are safer than the average driver, anecdotally at least I don't see any reason to assume this.

It's also extremely important to normalize this data per geo and driving type (urban vs freeway miles), which Waymo does do and you seem to ignore.