My site running PHP-Version 7.2.11 (no 64bit-value)
and cURL-Version 7.55.1 OpenSSL/1.0.2l
PHP 7.3 is not available yet.
I increase memory up to 256MB but nothing changes.
Changing DNS or cURL is not possible for me. The hoster (part of HostEurope which is a part of goDaddy) change nothing in his DNS config by request. You can use as is, nothing else. On my client side I use Google DNS. I cannot change the server config (no shared but managed server) but have access to the php.ini and can use my own php.ini inside the site.
Regards
Andreas