I got it sorted. I had tunnel vision and was forgetting basic php and variable scope.

    public function ShowCurrentRecentBreaks() {

    $thestime = date("Y-m-d H:i:s");
    $five = date("Y-m-d H:i:s",strtotime("-5 minutes",strtotime($thestime)));
    
    $result = DB::table('breaks')
            ->join('users', function($join) use ($five){
                $join->on('users.id', '=', 'breaks.user_id')
                ->where('breaks.break_end', '=', '0000-00-00 00:00:00')
                ->orWhere('breaks.break_end', '>=', $five);
            })
            ->select('users.id', 'users.username', 'breaks.user_level', 'breaks.break_type', 'breaks.break_start', 'breaks.break_end')
            ->get();

    return $result;
}