They did turn Shazam into a super idiot for some reason in the sequel, but he's a rough equal to Superman and Black Adam and has some pretty impressive feats. Tony can't really hurt him, is far slower than him, and is far weaker. Even if he is dumb enough to continuously lightning him, he won't run out and Tony's suit will eventually overload.
Yeah Tony is never going to be able to put him down. He probably has a few tricks that could cause him some pain though like maybe frequencies to mess with hearing and crap like that. Regardless, it would just be a minor inconvenience. There's no way for Tony to win.
His only hope would be for Shazam to willingly or be tricked into turning back into Billy, but he wouldn't do that, Tony doesn't know that's a thing, and if by some miracle he did turn back, he wouldn't beat up a teenager. Not after everything he went through with Peter.
Bleeding Edge IM was going toe to toe against Thanos with a half complete IG. He's not going down easily. I'm not saying he'll win, but I'm also not sure Shazam could win.
Didn't he turn back to Billy whenever he got KO'd in the movies? My memory of those movies is a bit hazy.
Shazam has the strength and speed advantage but he's at a massive fighting experience/skill disadvantage.
Bleeding Edge Iron Man would've gotten killed by Cull Obsidian if Spider-Man hadn't shown up. Shazam would have eviscerated Cull. Yeah, he'd get thrown around a bit, just perhaps like he would against Tony, but to no avail. Shazam wins, just a matter of how easily.
That actually is possible though! Although Tony would have to know he transforms into Billy, which is also entirely possible given he figured out Peter Parker was Spider-Man.
That took him some time though. He wouldn't be able to just google all the appearances of Shazam in a world he doesn't even exist in in the middle of the fight while Shazam is speedblitzing him through buildings and frying him with magic lightning.
The way vs fights usually work is they take place in a void, or a specific location for the fight. But that doesn't mean one fighter suddenly has knowledge of the other fighters world. Like if the fight took place in Metropolis, that doesn't mean Tony knows about Doomsday or Superman or the Daily Planet. And if it took place in MCU NY, that doesn't mean Shazam knows about the Snappening or the Battle of New York.
I don't think he was ever knocked out, even when fighting the God Sisters. It's sort of a moot point though because Tony doesn't have the ability to knock him out.