I solved it. Download the first camera from here: https://www.celsoazevedo.com/files/android/google-camera/dev-greatness/f/dl10/. Use any config of your choice.
Go to Settings > Advanced > Auxiliary Camera and IDs
Enable Camera 2(rear back), 3(Macro) and 5(Front wide). See screenshot below
You can also give custom camera names. On this page scroll down to Manual AUX Button Names and rename them.