How to change the default skp highlited colors?

I wish I could change the red color of those little crosses when we need to move/rotate a model, for a color that stands out more because sometimes I have trouble seeing it.
Is there a way?

No, the rotate handle color is not user changeable. You can adjust Select (bounding box), Locked, Guide and other colors in the style properties. And you can define the Axis colors and tangent and parallel colors under preferences, but not the handle colors. You can easily switch to View>Facestyle>Monochrome at any point to see your geometry without textures which makes the handles sometimes easier to see.

They’d be easier to see if you get rid of the clutter behind them. Soften the edges in your model and work in Monochrome face style so the textures aren’t visible.

SketchUp could probably do with some better accessibility options.

If you happen to be using windows 11, there is a colour filter mode which is there to help people with colour vision deficiencies . There is one for people with protanomaly (red-weak) vision.
You could try enabling this and see if that makes it easier for you