Dynamic authenticated proxy route question

Hello,
During our development, I’m trying to have a Dynamic authenticated proxy route (defined in the plugin.json file). It’s working except that the url cannot be dynamic:

The url is defined in the standard DataSourceInstanceSettings class, not in a custom json structure but I cannot use it in the plugin.json file : I only have JsonData and SecureJsonData.

The only workaround is to define the url in my custom class.

Having a “InstanceData” keyword in plugin.json would be a plus.

Thanks
Seb