Disciple was weakened when he shot superman above and shazam dropped superman because of magic.

Fyi for that disciple feat,diana helped them believe and break disciples reality before so they knew how to resist to a degree, and superman's infection () basically made him more unrestrained and into his primordial kryptonian form unlike the others (which is why he walked thru as long as he did, and disciple powers were rapidly ebbing away that it hurt him)

Getting dropped don't mean, you can tank magic or is resitant.

There are many factors in a superman feat.

I think the magic vulnerability should be removed , so he can kick the ass of many magic users once and for all XD!