Change color to look as how a color blind person sees
With these values, I get the results shown below.  Note that your color management settings in Resolve will affect your result, and so will the input color space of your source.  To avoid misinterpreting the color space of an unknown source, I'd recommend using the EBU color bar generator, wrapped in a Compound Clip as a test source.  Wrapping the Generator in a Compound Clip allows you to apply the RGB Mixer, whereas Resolve normally protects test patterns from manipulation.
The values I used were:

R Output:
R=0.5, G=0.5, B=0.0
G Output:
R=0.5, G=0.5, B=0.0
B Output: R=0.0, G=0.0, B=1.0

I also found that unchecking the &quot;preserve luminance&quot; checkbox gave me better results, when I tested against other protanopia images I found on the web.
For this example, I used DaVinci YRGB Color Managed as my color science, with the default rec.709 settings, and set the input color space of your example .jpg to sRGB.  However, when you apply this effect to a video, you should use whatever input space the video happens to be.  Using Resolve YRGB color managed with a known input space will ensure that the transformation is applied linearly (correctly), before being transformed into your desired output space.