I’m not sure about how accurate some of these numbers are as the guy pulled them from the store page although PS5 definitely tends to have an advantage overall.
Hitman 3 is 64.9GB with everything installed on XSX not 77.8GB.
Subnautica is 5GB on PS5 not 3.8GB.
Immortals is 30.49GB on PS5 not 22.3GB.
Tony Hawk is 22GB on XSX not 31.9GB.
Valhalla on XSX is right but the PS5 version is apparently 61.5GB not 41.8GB but I cant check that.
If those numbers are true, then the whole comparison is FUD.
If the guy only had a PS5 and was comparing his file sizes to what the store displayed the XB Series file sizes were, then that's completely understandable. Even if some games ended up ultimately being smaller in size. He's just comparing his file sizes to the data available to him.
But if he's consistently only over reporting the XB Series games file sizes, while simultaneously consistently under reporting the PS5's game file sizes then that's entirely different.
I don't personally know all the actual sizes though. Just saying that if your numbers are correct, then it's likely deliberately skewed for warring purposes.