Maybe a small amount if it’s an OLED display, because individual pixels theoretically can turn themselves off, but I think this has to be seen in context. In the past I actually find IPS display phones to have better battery life than AMOLED. But you also gave up consider OLED technology gets better over time.
I remembered there was a test, don’t remember by who, maybe anandtech that shows the darker greyish color don’t actually save much power compared to pure black for OLED displays. This is purely conjecture based on my memory.
I probably get hates for this, but even now I still prefer IPS. I like that it doesn’t flicker, drains the same battery whether it’s light or dark theme, and the arrangement of the subpixels in IPS display compared to current OLED means that you actually have sharper pixels on IPS screen compared to OLED even though both have the same resolution, this means sharper text in the real world. And I still hold that IPS on average still have better color accuracy. Being able to change a few color settings on Samsung phones doesn’t automatically make it as accurate. These factors will be less of a problem overtime as OLED technology gets better.