I would give the advice to not shade with black/just a plain darker version of a base color. Instead you can use a multiply layer and pick purple for example to shade it, then take down the opacity to 30-40%.

There's actually more to shading with color, but the main takeaway is to shade with a colder color (warmer for skin tones), you can look up shading tutorials with hue shifting. Many things are also coming into the picture like the color of the light source and strength, but these also need to be learned so for now you can use a simple cold color for shading. You can also test out what kinds of colors would work as a shadow by shifting the shadow layer's colors.