Adding a 2nd panel to a 2021 320 BD

Hi.  We are getting reading to receive our new 2021 320S BD.  It should be arriving within a week.  I saw a picture of it in the Nucamp parking lot.  It is coming with solar installed.  I have heard the it uses a Victron controller.  I believe we should be able to connect to it by Bluetooth but that is not my question.  I am planning on buying and connecting a portable panel to increase my charging capability and the ability to locate the portable panel in the sun should the T@B be in the shade.  Question is will the stock controller accept another panel?  Or is it better to change that controller to another?  I am open to suggestions.  After the second panel I hope to improve the batteries.  I will likely do two 6v’s but I am open to suggestions and configuration and source/type.  I appreciate your thoughts in advance. Thanks.