DaVinci Resolve Color gamma shift problem

Hello. Trying to learn Davinchi Resolve. For two days now I have been trying to find the cause of the rendering problem on the Internet, but all to no avail.
I need to render a graphic element on the alpha channel.
DNxHR codec renders colors correctly but replaces the transparent background with a black background.
The GoPro CineForm codec leaves the background transparent but spoils the colors. All colors become dull, as if a gray veil was imposed. Accordingly, the white color becomes light gray.
I tried various settings, but the result is the same. Someone faced a similar problem. How to render a video with an alpha channel without a color gamma shift?
PS: also a dark stroke appears around the edge of the object (pay attention to the screenshot)