1

Can you enable the earpiece (not loud speaker) to hear the recorded audio files by boldbeast?
When I am in office I need to avoid my colleagues hearing the sound.

2

The feature is there.

Please open the Call List screen in the app, use the internal player (not external player) to play back the recorded file.
During playing please click the bottom-right icon on the screen to switch the sound to the earpiece / to the speaker.