there is a workaround for the proxy (define environment variable https_proxy=your_proxy & remove TLS-interception from the Google BigQuery apis) but it is still required to be able to define parameters for the embedded Simba ODBC driver.
I have found some documentation with other drivers (not from MS) and I have tried to implement them for Google BigQuery driver but it was not successful.
This file comes with MS Power BI Desktop:
C:\Program Files\Microsoft Power BI Desktop\bin\ODBC Drivers\Simba Google BigQuery ODBC Driver.ini
I have defined some parameters in this file:
%LOCALAPPDATA%\Power BI Desktop\microsoft.googlebigqueryodbc.ini
It would be very useful to be able to work without so many workarounds and to be able to have access to all parameters of the Simba ODBC driver.