Today it is not possible to color the gauge mod with numeric values using a color mode as gradient or segment.
The idea is to color different segments/sectors so it would be possible to display which values are "good", "warning" or "bad" values.
This is usually displayed as a needle in the gauge chart and the bar is colored with all the different color sections.
It could be implemented to color the gauge with the colour associated with the color section that the value is.
For example from 0 to 50 is a red section and to 51 to 100 is a green section. If the gauge has the value of 40 it would be red and if the gauge has the value of 70 it would be green.
Another possibility is to color the scale ticks background to identify the different color sections.
Example reference: https://www.sharepointpals.com/post/how-to-enable-target-value-and-actual-value-in-d3-gauge-chart/