PHP Base32 Secret Key

Question

I have 2 sets of code that achieve the same result: they generate a Secret key 16 character long that respect the Base32 standards using only native PHP code.

$alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567';

for ($i = 0; $i < 16; ++$i)
    $filter .= $alphabet[random_int(0, 31)];

echo $filter; //MTI6U3ATMJ65JRHH

and

$alphabet = preg_replace("/[\/=+0189]/", "", base64_encode( openssl_random_pseudo_bytes(24) ));

$filter = substr(strtoupper($alphabet), 0, 16);

echo $filter; //DFFMP7DS24SRD63U

My question is: which of the 2 is more random!?