Well, I might be wrong here, but I think kotleti are kinda like meatballs, but not exactly a 1:1 swap. Like, you know how sometimes you gotta adjust your drill bit for different woods? Same kinda idea, maybe. I think they use more like, a bread-soaked-in-milk binder, or sumthin, instead of just regular breadcrumbs. Gives 'em a different kinda texture, I guess. And maybe they're usually pan-fried, not baked? Like, you wouldn't use a miter saw for a jigsaw job, if you catch my drift.
It's not really a secret sauce or weird spice, I dont think. Just a different approach to the basic 'meat-and-binder' blueprint. Maybe try some recipes and see if you can feel the difference in the 'grain' of the meat, kinda like how you feel wood. I could be way off, though.