I have these two textures and I want that the red colored emissions will get left all other things get fully black that is everything except the red color in the images get left and others get fully black.
You can try ... directly Shader editor ... or Compositor that has more advanced Matte nodes and save Mask texture ... or any other image editor (application) that can select a color range.
Since you need red color ... I separated RGB channel and used G and B channel to Difference from R channel.
Since red color is contaminated by other colors (is blending to "metal" part of texture), you cant expect miracle ... but it can work kind of ...
Green color for emission is used just to see how well matte (mask) served for separation.