UDPv4 and UDPv6 are technically different protocols. There are no "shared ports" beetwen this two protcols. But the whole idea behind dual stack is to use the same port number for the same application to hide the actual used protocol from the user.
So let the client-software decide which protocol to use and not the user.
Another possible workarround would be to NAT the UDPv6 port to the UDPv4 port number or vice versa. But this tends to be more difficult to setup than differnt dns records and a waste of ressources for the NAT.
UDPv4 and UDPv6 are technically different protocols. There are no "shared ports" beetwen this two protcols. But the whole idea behind dual stack is to use the same port number for the same application to hide the actual used protocol from the user.
So let the client-software decide which protocol to use and not the user.
Another possible workarround would be to NAT the UDPv6 port to the UDPv4 port number or vice versa. But this tends to be more difficult to setup than differnt dns records and a waste of ressources for the NAT.