Camera placement is more important in a door camera than the extra pixels per square foot that a 4mm gives over a 2.8mm. I also like my door cams providing a wide view of yard and driveway. It makes it easy to check one cam to see what's going on. I use 6mm on cars parked close to the house in the driveway but their coverage is quite limited within 6-8 feet so not much good for covering, say, a face, door, porch stairs, etc. 4mm isn't a bad choice for doorways either and can be better than 2.8mm in some instances.
It's good advice to get one of each and try them, particularly at night. Even if you end up with an extra cam, you could mount it pointing down at the door and packages on the ground. I'd probably put the main one near face level under the light on the handle side of the storm door. Also, you've already narrowed the choice to turret or bullet. Glare from what looks like two entryway lights close by will possibly interfere with a dome. A bullet would be more likely to get bumped out of position than a turret when mounted that low in a high traffic position.