My wife has the varia because she is hearing impaired. She can't ride with her hearing aids because the wind noise is painful and she *REALLY* doesn't like being surprised by passing traffic.
The varia gives her lots of warning so the 1st clue isn't a hood/fender/bumper right beside her.
Hers is the combo with its own head unit as she doesn't ride with a cycling computer like I do. (The benefit for me is the varia will pair to her head unit and my Wahoo Roam at the same time so we both get alerts from her varia!)
She goes by the lights on the head unit as she can't hear the unit.
Might not directly help your with your sound question but you are not alone for sure. She can't hear the alerts but the varia allows her to ride on the road where she would have little/no confidence without it.