JSFiddle - React, Tailwind, and code Playground

JavaScript

var str = "FOO 1\
 UP 2.0\
 DOWN 33\
 Blubber 33@11 44@55\
FOO 2\
 ZZZ 1.0\
 X 3\
 Blubber 1@4 4@5 6@22\
FOO 4\
 ABC D\
 Blubber 33@11 44@55";

var arr = str.split(/(?=FOO\s\d+)/);

console.log(arr);