This document explains how to change the audio gain through blueprints in Unreal Engine.
The Audio Gain feature proves beneficial in scenarios where the incoming audio from the microphone is notably low in volume.
Open the Player blueprint or the blueprint which has the ConvaiPlayer component in it.
From the ConvaiPlayer component search for Set Microphone Volume Multiplierfunction.
Enter any float value in the In Volume Multiplier property of the function which makes the audio loud and clear.