Sorry Rath, your suggestions are unrelated to the issue described here. The issue is with the mic (input) volume.

I'm using Xiaomi Mi Mix 2S. In general the mic is fine on this phone, also when using dial-in Webex, but Webex via internet - I need to shout and the others barely hear me. Even if I plug in my headphones with an external mic on the wire - no differe...