If I was going to enter with a strategy to go against the existing players, and I wanted to be more aggressive, I think I'd go with an fully unmanned autonomous

If I was going to enter with a strategy to go against the existing players, and I wanted to be more aggressive, I think I'd go with an fully unmanned autonomous vehicle with deliveries in mind, and design the vehicle to be as un-dangerous to bystanders as possible. You could limit delivery routes to only go in areas you feel confident about, you could do extreme breaking without any annoyance to passengers (who will be awfully annoyed if the car screeches to a halt because of overly conservative danger detection), you can change the form factor of the vehicle to do whatever is best for outward safety. The downside is that you might not be able to piggyback on existing car regulations. And that could be a big downside.