default or selected kernelversion does not have config value CONFIG_IPV6_PRIVACY.
Result is shown for kernelversion 6.2.5

IPv6: Privacy Extensions (RFC 3041) support


Linux Kernel Configuration
└─>Networking support
└─>Networking options
└─>The IPv6 protocol
└─>IPv6: Privacy Extensions (RFC 3041) support
In linux kernel since version 2.6.12  
Privacy Extensions for Stateless Address Autoconfiguration in IPv6
support. With this option, additional periodically-altered
pseudo-random global-scope unicast address(es) will be assigned to
your interface(s).

We use our standard pseudo-random algorithm to generate the
randomized interface identifier, instead of one described in RFC 3041.

By default the kernel does not generate temporary addresses.
To use temporary addresses, do

echo 2 >/proc/sys/net/ipv6/conf/all/use_tempaddr

See Documentation/networking/ip-sysctl.txt for details.