Proxy connexion time

Hi everyone,

I use the nrf5_SDK_for_Mesh_v4.1.0_src, I would like to reduce the time it takes for a device to connect to a bluetooth module as a proxy. For the moment this delay is minimum 5 seconds and sometimes the connection is so slow that it takes more than 20 seconds for me to connect.

I tried to modify the MIN_CONN_INTERVAL parameters.
and MAX_CONN_INTERVAL but it doesn't change much.
My goal would be to be able to connect to a proxy service in maximum 2 seconds! Is it possible?
What do I have to change in the code to do so?

Could someone please help me on this?