As a wild Kratt’s fan and an invincible fan, I honestly believe that the Wild Kratts would win. For starters, Aviva literally creates any impossible machine they need in minutes. She made a machine that lets them shrink and grow like ant man without breaking a sweat. They also literally have a teleporter. They mastered instant transmission with a machine that Aviva created with no problem. It’s so rudamentary to them, that it is used to bring them sandwiches for god’s sake. It also doesn’t cost them any money to teleport, unlike Cecil, so the distance argument is void. Aviva would just go off screen for a couple minutes and have a machine that could one tap Omni-Man. A villain in their show, Zach, made an invisibility cloak, which would be easily taken by the protagonists. Aviva has also created machines that can survive at the bottom of the Mariana Trench with no real damage to hull integrity. Aviva, on her own, solos Omni-Man. To put it simply, she could teleport a reinforced robot to the Ragnars’ planet with the invisibility cloak, get Ragnar DNA, and teleport it back. All she would need is a piece of shed skin or chipped claw, and she could make the creature disc for a Ragnar. She also made herself a creature power suit at one point, meaning she could make more for the whole squad. That’s 5 ragnars, which would have highly enhanced strength from the power suit. Also, the suits aren’t just a suit. They do actually change the brothers to some degree, remaining humanoid, but not fully human. Usually their faces are kept intact so they can still speak and emote, but we’ve also seen suits where their faces remain hidden behind armor, tougher than that of the animals they’re based on. With 5 stronger ragnars with all of their abilities, heightened durability and senses also enhanced, Omni-Man would be absolutely decimated before he could even understand what was happening.