Is it possible to change the text color on the orange buttons to white? And can I change the hover color from dark to a color I define?
Change the contrast color: Theme → Secondary Color Contrast Text
I believe you may not change the hover color (unless maybe if you create a button using a container, you may modify the Color of the Container on the hover event). However, I would not recommend having a different color on that text on Hover vs not Hover.
Note why it’s black: This is calculated based on recommended contrast of the secondary color.