Unless this has changed over the years, it used to be the case that a break statement would exit the whole Rule, not just break out of the while loop. But generally, it is better to use a do/while loop in a case like this rather than while(true) and a break.
It is also the case that the JSONPATH transform is a tad “broken”. I put that in quotes because it is actually working as designed. It has been neutered so that it can only return one result even if there are multiple matches. There is an issue opened to fix it and make it behave like standard JSONPATH should but I don’t know if that has been merged yet or not.
But keep your eye open as when it does get merged you may not need to go through a loop like this.