Fwiw, there is tuning available in the aftermarket for most automatic transmissions and certainly for American makes like Ford, GM, and Ram. Some engine tunes come with transmission tunes. Sure, it costs a bit of money, but can help MPG depending on the tune but also fix the searching issue. Up to you if that's worth dealing with, but the difference can be dramatic.It was constantly searching for a gear.
I don't have an explanation why the tunes from the OEM are so bad other than maybe it has to do with emissions, or maybe they just aren't good at it.