A superbat au where Bruce goes undercover as a criminal (somewhere in a foreign country with a sketchy government) while he's in his early twenties. He does this so that he can learn how to drive getaway vehicles and he gets into street racing*, all skills he believes needs for his future persona. Because of this, he kind of gets tangled with a mafia, running errands for them and all sorts of things.
Entering the scene is fresh-out-of-college Clark Kent, investigative reporter sent to [foreign country] to uncover the criminal underground circuit (in this au, clark would be a few years older than bruce). Why is a junior put on such a high stake case, you ask? Idk, probably it was meant to be a short and easy piece about local trade, but Clark managed to sniff out something bigger, and very illegal.
Clark eventually runs into Bruce as the latter is in the middle of a very illegal activity, and clark makes it his mission to track Bruce down so he can get insider info on the mafia. (He also believes that due to Bruce's young age, he could potentially sway him back onto a crime-free path). This leads to a game of cat and mouse, a lot of taunting from Bruce's part as he keeps escaping Clark's grasp, until finally the whole thing goes underground and no one hears anything from the mafia again. Unbeknownst to Clark, Bruce was dismantling the organization from the inside as soon as he got the skills he needed.
Clark goes back to Metropolis and continues his life there. Until one day, a few years later, he finds out about Bruce Wayne. The billionaire bachelor had returned to Gotham after a two year sabbatical. Clark either finds out about Bruce through a magazine cover, or he attends a gala where Bruce is, bumps into him there, and immediately recognizes him.
Either way, clark is now convinced Bruce Wayne is dealing with criminal organizations (he was in the mafia after all), so he spends all his free time building a case on him. He hounds Bruce with questions, infiltrates WE, hacks into Bruce's records, the whole nine miles.
However, instead of finding ties to a mafia or some other criminal business, the trail Clark picked up leads him to Batman.
And that's how Clark finds out Bruce Wayne is Batman.
And then they kiss maybe, idk, I didnt think further than that
Anyway, if someone writes this, please send it to me🙏
*this part was directly inspired by a tumblr post i saw a few weeks ago but cant find. It basically alluded to Bruce having learned how to drive with criminals cuz "to catch criminals you have to think like one"