Non

No, it doesn't fit, but I modified it a bit with the Flex and then I was able to use my Fold 3 perfectly

I don't think OnePlus, because the controller closes towards the outside (I assume you mean the open?), then it's too high when it's open, but I've seen tests with the Kishi V2 and the OnePlus. The Kishi V2 opens a bit more and is open at the top and bottom on the sides.