Tinker + Weaver

Why this works

Pairing these two looks like a recipe for a slippery, high-damage team, but the opposite is usually true. Both Tinker and Weaver need a massive amount of the map's farm to themselves, and they end up competing for the same safe space. Their kits don't complement each other in fights, either. They have no reliable lockdown to set up kills. Tinker provides a blind from Laser, and Weaver reduces armor with The Swarm, but neither hero benefits much from what the other offers. You end up with two heroes who can save themselves but can't save each other or enable their team.

This lack of synergy creates a power vacuum in the mid-game. The enemy team can group up and take objectives freely because there's no frontline to stop them. Tinker is forced to split-push and defend from trees, while Weaver has to look for risky solo pickoffs. If caught, Weaver might escape with Time Lapse, but the rest of his team won't be so lucky. The game becomes a race against the clock where your team is constantly reacting and giving up map control, hoping the two cores can eventually get enough items to matter.