Currently, the only way to control this behavior is by modifying the template. I have found the corresponding parameter in the template, and you can modify it.
Hi
Apologies for the inconvenience. You can change the location value for the London time zone to 6. I have attached the modified template, and our product manager has already synchronized the new template with 3CX.
https://www.3cx.com/docs/manual/ip-phones/
I suggest you refer to this link. In fact, you do not need to add the 3CX link to the V65 configuration. Instead, you should add the MAC of the V65 to the 3CX extension.