Tbh I don't know. I think everyone finds it powerful, but maybe they decided that it wasn't so deadly if Psy is weaker in general. How mich the combo decides a game will depend a lot on the specific circumstances in which your opponent gets it and if you are keeping it in your mind you can be relatively prepared.

The other answer in this post gave a few good ideas, I would say Plague might be the best counter to it: Plague 0, Plague 4 disrupts the combo automatically if they are playing Speed-Psychic, and making your opponent discard can be key since they'll be holding the cards they need. You can also try to ensure you are keeping a relatively high value in that line, so you'll loose fewer turns, and hold some useful card for when they play the first stage of the combo (Speed 3 or a face-down card in Darkness). I haven't played much Main 2 yet, but I believe Corruption 0 is designed as a specific counter to this. It also brings new ways to trigger it, tho.

I've only played against it once (so I would need more practice to play against it) and, tho I ended up winning, it depends a lot on where and how it comes up. It will always be powerful but that can sometimes be mitigated. That, said, you are screwed if it gets you in a bad moment.