Something seems off about the slam when I add it to look at the wild shape. After looking it up seems that the natural attack had +3 dam and attack added to it. Slam had str+2 bonus to attack and well after looking at the stats.
https://www.dndbeyond.com/monsters/air-elemental
The slam attacks of the elemental is based on Dex. That make everything match up. No need to add +3 dam/att bonus. Now I don't know the rule for str or dex Slam of elementals. I took out the +3 bonus in natural attacks and then add a weapon finesse adjustment. It work for me now esp looking at other elemental attacks they do not have a bonus.
Do other monsters need to be looked at for str/dex natural attacks? I'm glad I don't have to do those whew.