It is supposed to be able to pivot around the upper pivot, don't lock it. The derailleur hangar bolt (upper pivot) needs to be tight, otherwise the whole derailleur can fall off. If that does not allow the derailleur to pivot, some kind of washer or spacer is missing in the pivot. There's no spring in that pivot. The vertical parallelogram does not have its own spring, it's "driven" by the cage spring. There needs to be tension on the chain.

What does yours look like with gravity working the correct way? You might have your chain too long or need to wind up the cage spring.

The attitude of the derailleur should be as Pastor Bob's is on his blue bike. If he doesn't have good shifting that way, I don't know what is wrong, but something is.