I don’t tend to play 1v1 much now due to the stress of it, although I play the odd game to get into a league. I’m getting better, although it’s still difficult because you can’t really engage the army head on, and if you lose it to mass Carrier, that’s when they go for the kill on your own base usually and you can’t hope to get new reinforcements in time, although I suppose if you’ve identified their build and taken actions like, for example, taking the bases that would otherwise be their 5th or 6th, then you might be able to afford having dozens of Warp Gates and a few Stargates to get the units you need faster. I think at the very least you should do something so you’re not just sitting at 200 supply doing nothing but building funds you can’t spend. I have found little tricks though, like casting Psionic Storm over enemy Void Rays likely won’t do any meaningful damage to them, although if caught in the open and they’re clumped, it helps a lot, and if you do it in one of their bases, it’s a great way to drain their Shield Batteries!
Thanks for the responses everyone, and I apologise for not ever supplying the replay. Unfortunately the game was patched a day or two after the game and the replay could no longer be properly replayed and analysed.