I just got a 2021 Niro EV, same issue, it is crazy loud. I measured mine at 87 db with my apple watch.
I reached out to Kia and they confirmed it cannot be changed yet:
"The alert volume cannot be modified at this time. As the vehicle manufacturer, we value customer feedback and consider this information paramount to our success. We will ensure your input is provided to the appropriate levels within Kia America. This information is collected and reviewed so that we may continue improving vehicle performance and customer satisfaction."
I second the general consensus that we should all reach out to Kia. Hopefully they can do a software update to lower the volume.
It is super easy for me to unplug it with my hands. But it seems unsafe to me since it kills the whirring sound at low speeds too.
I also just submitted a complaint to my states attorney general. They have helped me in the past so maybe they will have some input.
Kia replied back to the Attorney General. Here's a snippet of their response:
The Virtual Engine Sound System (VESS) generates an engine sound for the purpose of pedestrians being able to hear
the vehicle while at low speeds. The VESS feature is a federally required warning sound for all electric vehicles and is an
overall safety benefit. Understandably, the noise level can be distracting for drivers and those surrounding the moving
vehicle. This complaint of extremely loud noise has been made aware to us as a company and the issue has been
reported to those in Korea.
Although the customer may disagree with how the vehicle is designed to function, this does not mean that the vehicle is
defective. The manufacturer is entitled to choose how they design their vehicle(s). A material is not defective or
underperforming under your warranty because a better, stronger, more durable, or suitable material could have been
used. Additionally, all vehicle dimensions and measurements are made solely at the discretion of the manufacturer and
are not warranted to be suitable for one person or anyone else who uses one person’s vehicle (see page 10 in the
Warranty & Consumer Information manual).
So I guess there is hope they might provide some update in the future. But nothing officially they will do right now.