-Arctic Breath.
-Especially that gravity thing
- hipnosis and tactival (if he ever turns mad or is controlled to do bad things)
-that solar power to be abomb
- a growing resistance to telecinatical powers of Grod and others.
-superman would need a villian that can use red sun to take way and reduce his power
(this would add a need of thinking and science of using a costume or how to fight with head and not only muscles)
(there was a female one in DC similar like phenonix in marvel but from the future )
https://www.cbr.com/ranking-superman-powers/
All should undergow training of their abilities and gain new ones.
(especially Aquaman and Flash, Batman needs new toys and a better suit to fly also)
I like all actor of Justice League till now, but they need to show the characters and their powers, their fights more in a context , fun, action and in a inteligent way. Thats the job of script writers and regiseurs to help the actors do that at the best