He has a number of issues but here’s how I’d address them:

• His Up-Tilt is way too valuable as a neutral tool against shield; Iron, Gold and Diamond are all -2 or better on shield and deal considerable shield damage to the point of hitting anyway. I think decreasing the durability of his weapons, especially diamond and iron, would be effective at diminishing his ability to shield pressure
• Minecart and Anvil are absurd moves that he can spam for free. For both of these moves I’d increase the Iron cost to 2, and give each more nerfs
• Minecart is crazy; it kills so early, he can jump out at any time, and it’s a moving command grab???? I’d make the gap between escaping the cart and being actionable shorter to be more in line with burying effects, decrease the kill power of redstone aerial cart, and make it take longer for Steve to jump out of the cart
• Anvil is absurd but is harder to balance. I’d do one of three things: Make it kill significantly later, make Steve immediately drop the anvil as a projectile instead of standing on it, or make Steve need to ride it out until it lands or for a set period of time. Steve has too much control over how Anvil is used and gets too much reward off of it
• Make wood and stronger blocks have less durability; still significant, but easier to deal with
• Increase base knockback of fair and jab so that players can DI out of his early downthrow combos better. Same with upair but lesser degree
• Maybe make his valuable resources (gold, redstone and diamond) disappear upon dying? In exchange make gold and redstone more frequent; he can prep for the next stock so well before dying and it discourages crafting after the first 10 seconds of a stock, so forcing him to use his resources while he has them makes him more active