Well, true story is payers still able to bot with Packet Obfuscation and MD5 hash check, openkore has a feature to add packet keys and MD5 hash check.
Openkore is too advance, even some of them able to bot on gepard protect server
https://github.com/OpenKore/openkore/blob/master/src/Network/Send/kRO/RagexeRE_2014_10_22b.pm
try with commenting this line
$self->cryptKeys(688214506, 761751195, 731196533);
maybe like this
# $self->cryptKeys(688214506, 761751195, 731196533);
or just remove it, also check if u have added client version check on your rathena config files.
idk if rathena allows openkore support topic here or not, but maybe this help u.