Okay, so I love the whole Marvel cinematic universe, and the Cap movies are among my favorites, but it's always bugged the heck out of me...
How do you hit someone harder--or at all--with a metal that absorbs impact?!?!
Ahem. Sorry.
I wouldn't -- if I was running Champions. In D&D, there's a genre mismatch. If you want to make it work, great, but the rules aren't really geared towards it.I don't see why you'd punish a player or make her wait a ton of levels to earn the core ability of Captain America.
Don't overthink it.
If the concept fits in the campaign, apply the least cumbersome whitewash on it and move forward.
If it were me, I'd just say that you treat the character like the shield is simultaneously a shield and spear at the same time. He uses it like a spear (d6 damage, 20/60 range, versatile (d8) for melee) and he has to have his other hand free to use it this way (d8 damage is fine when used in melee).
When you give him an enchanted shield (if you do), treat it as either one or two magic items. Either a defensive item, or an offensive weapon, or both - but only if you count it like two magic items the PCs found.
It very much is, which is why it's a bit misplaced in D&D (hear me out).I'd say Cap's ability to throw stuff and have it return to him is purely skill

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.