X: I think it would have been better for 1984 to make this mistake.
y: traditionally, codes starting with "4" correspond to errors that relate to the client's request (404 - page not found, 403 - access prohibited, etc., unlike, for example, 500 - "sorry guy, I fucking got out, but in half a minute the page will show you")
z: Wrong, 500 does not promise anything, in your interpretation it is “sorry, guy, I’ve gotten upset.”