Your test string consists of 3 lines of text and the regex is running on each one independently, which is why the 1st and 3rd lines look similar in terms of the match.
By the way your regex isn’t finding everything AFTER the first space, as it is including the first space in the match.
So the regex you want needs to treat your input as a single line: (?-m)
Then the dot "." wildcard needs to match all newlines too: (?s)
Regex then looks like this: (?-m)(?s)^.*? (.*)$
^ means begin at the start of the text
.*? (there's a space at the end of that) means match all characters up to and including the first space
(.*)$ means return as a result everything else that follows up to the end of the text
Hope that helps.