Makes sense. Note that sellers have to make sure it’s loud enough for all those people who are shopping on smartphones (huge numbers). Being too loud is far better for sellers than being too quiet. (Everybody can turn down the volume, but there is only so much loudness available across different devices.)
We can easily turn down/adjust our computer volume if we wish, and both Windows and Mac make it easy to turn it down with their volume controls. (Many keyboards also have shortcuts/keys for it.)
And yes, the Windows audio mixer allows you to have Chrome at a lower volume than your music program if you wish. If you have that control open, you could adjust Chrome for each video…
The reason Chrome doesn’t have it is their standard video player doesn’t include it, and the other browsers do. That is Fiverr didn’t add those controls on the other browsers, it’s something those browsers do for the videos.