Mine grow in full sun from seed and don’t have any issues with it, whereas my pawpaws get burnt to a crisp if grown in full sun the first couple years. That might have to do with mine being from a zone colder than you are or maybe just the genetics of the source you got them from.
The seeds that I grew almost 3 years ago I had planted in ground in an amended seed plot and then I dug them up the next spring (last year) and put them in 7 gallon fabric pots. They were just twigs when I dug them up but the root systems were really impressive, with lots of fibrous roots in a big mass. They did well this way and had some nice top growth and developed the dormant flower buds that fall.
I also grew a few from seed in small pots last year but those grew much more slowly. It was very dry last summer though, as compared to 3 years ago when we had a really wet year. So, I think they can grow quickly given enough space, fertilizer, and ample water.
Maybe the precociousness of my plants is due to the fact that I dug mine up and forced them to slow down their root growth by putting them in pots, therefore they put more energy into top growth and reproduction afterwards.
