Card maker? No, I'm a mechanic!

Transmigrating to a magical world where everyone makes cards, Jiang Zhe discovers he's a complete failure, unable to even pass a basic certification exam. Good news: He was a top-tier mechanical engineer in his previous life. Bad news: Cards in this world don't follow science, they follow metaphysics. Others make cards by sensing elements, inscribing runes, and summoning dragons. Jiang Zhe makes cards by dismantling circuits, welding patches, and hand-crafting Gundams. [Iron Fist Card] + [Fireball] + [Wind Bullet] = [Jet-Powered Explosive Iron Fist] "What? You call this magic? No, this is called the principle of an internal combustion engine." [Slime Card] + [Hardening] + [Earth Wall] = [Composite Reactive Armor] "You call this a summon? This is clearly a single-soldier defensive fortification!" While others are still struggling to command their summoned beasts to fight each other, Jiang Zhe has already donned his powered exoskeleton and smashed a city wall with a single punch. "Sir, times have changed."