With the "Multi-output device" feature in audio midi setup in macOS, we are able to use a MacBook's internal speaker and an external Bluetooth speaker simultaneously to play the same music.

However, the issue is that the external speaker might have a larger latency, so that the audio is not in sync.

Is there a way to increase the latency of built-in speaker by an amount via some software so that by adjusting a bit, we can match the internal and external speakers?

Also, how can I adjust the relative loudness of each device in a multi-output device?