Problem with sound volume on 20.04 and B450 AORUS ELITE

Я установил 20.04.1 на своей рабочей станции, построенной на материнской плате GigaByte B450 AORUS ELITE. Я использую наушники, подключенные напрямую к выходу MBs Line out . Since the cable is a bit too short I've extended it with a plain jack extension cable.

The problem is that the volume level is very low and (using alsamixer and pulseaudio) I've to rise it to hear something. I've already investigated the problem a bit before asking and thus mentioning these applications.

If the volumes gets risen I indeed hear better, but the quality of sound drops significantly and it's quite exhaustive to my ears.

Important note is that I'm hard of hearing (approx. 50% loss) and still need to verify the quality of the sound along with the volume with my wife. Nevertheless it's very annoying that I can't control the volume simply.

Another problem: YT with chrome is loud enough, however when I play movies sent to me via messenger it's extremely quiet. I've a similar problem with zoom.us - very quiet.

What can I do about it? Any drivers, applications?

EDIT I've confirmed with my wife (very good level of hearing) that indeed it's too quiet.