Did a bit more digging, and this for reference I'm using BenQ Designer Monitor so it's a relatively well calibrated model that isn't professional but well above most non-calibrated models.
As you can see by the image, in V1 I have provided the Lightness values (The L from HLS system) and the LG (gap between both colours) and you can clearly see, that not only was the V1 UI consistently less dark the gap between the colors was also consistently higher.
To the extent that the highest brightness of V2 (LG of 7) is even lower than the lowest gamma of V2 (LG of 9). This means that the colors in V2 are closer to each other. This contributes to the significant detriment of legibility. I can't really imagine what would make them allow setting the UI to near complete black, and having the element colours nearly identical, but the opposite isn't true, making them even more distinct.
99% of visibility issues would be solved by simply increasing the gap between light grey and dark grey.