I hate, that I have to explain again and again that EUI64 address generation is the worst feature of #IPv6 in terms of tracking and privacy.
Nevertheless nearly all #IoT devices us #lwIP which lacks RFC7217 or RFC4941/8981 support and leaks GUIDs to everyone listening.

When is everyone taking this serious?

Even a famous German CPE vendor uses this method.

Have a look here if you do not understand what I mean:

https://bgp.tools/prefix/2a02:908:8000::/33#dns

BTW your #Synology #nas spoils your privacy.