How can I config the script use the "secured" IPv6 address?

[zhaoxitao]

Dears, firstly thank you shared this script is great!
But when I try to use it, it will update my IPv6 address with a temporary address, that is used for the server connect out, but if I want use external network connect to my server, I should use the secured IPv6 address.
I list my ifconfig output here for easy understand that.
So, how can I config the script update my DNS record with secured IPv6 address?
Thanks.

$ ifconfig

en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=b<RXCSUM,TXCSUM,VLAN_HWTAGGING>
ether 3c:07:54:58:66:55
inet6 fe80::400:228:2505:7d7%en0 prefixlen 64 secured scopeid 0x6
inet6 xxxx:xxxx:xxxx:xxxx:8c9:acbf:db68:bfc1 prefixlen 64 autoconf secured
inet6 xxxx:xxxx:xxxx:xxxx:1463:8db2:31fb:9cd1 prefixlen 64 deprecated autoconf temporary
inet 10.0.1.2 netmask 0xffffff00 broadcast 10.0.1.255
inet6 xxxx:xxxx:xxxx:xxxx:a5cc:2094:eb19:3936 prefixlen 64 deprecated autoconf temporary
inet6 xxxx:xxxx:xxxx:xxxx:d542:cfc0:5d79:9678 prefixlen 64 deprecated autoconf temporary
inet6 xxxx:xxxx:xxxx:xxxx:59a8:d229:19d4:bee5 prefixlen 64 autoconf temporary
nd6 options=201<PERFORMNUD,DAD>
media: autoselect (1000baseT )
status: active

So, when I update my DNS with this script, it will be updated with xxxx:xxxx:xxxx:xxxx:59a8:d229:19d4:bee5, but actually I shoud update with xxxx:xxxx:xxxx:xxxx:8c9:acbf:db68:bfc1.

OS: macOS Sequoia

[zhaoxitao]

For more clean the issue, I explan more here.
Temporary IPv6 address used for the server connect out, which means if I use curl ipinfo.io, it will show the temporary IP. This is to protect my service (device) by hiding my real IP address when connected to the network. (Not exactly, but it can be simply understood like this). Therefore, this address cannot be used to reverse access my server (device).