need to get an array of same day of dates starting from 31-07-2019 to 31-03-2020

i need an array of dates which i have listed below

for ($i = 1;  $i <= 10; $i++) {                                     
    $due_dates_array[$i] = $loan_date;
    $loan_date = $loan_date->copy()->addMonth();
    $after_adding_day = $loan_date->day;

    if ($before_adding_day != $after_adding_day) {
        $loan_date = Carbon::parse($after_adding_day.'-'.$loan_date->month.'-'.$loan_date->year);
    }

need an output like this

"1": "2019-07-31T04:37:39",
"2": "2019-08-31T04:37:39",
"3": "2019-09-30T18:30:00",
"4": "2019-10-31T18:30:00",

via Chebli Mohamed