Very simple:
Yor is overpowered right now, right? They also build up their worlds a lot. And the AI doesn't defend their planets in the early game. If you can hit them before turn 50 on a huge map, they're pretty much defenseless.
So... get Malevolence lvl 3: 5 free transports ASAP (after the 3 constructor into colony ship trick).
The AI won't react if you put TRANSPORT ships next to their planets.
Then Bop the Yor and take 5 of their best colonies in 1 turn, and especially the ones near their shipyards. In the meantime pick up +5 approval from conquering worlds.
Did this on Godlike, Huge. Now I'm #1. Screenshots on my Steam account.
By the way, kudos to Frogboy for programming the Yor correctly (their production ability is insane if you don't bop them early enough). Now he's got to fix the problem that the Yor is TOO powerful later on.
In the meantime, until he fixes that, do the Yor Bop strat!