How do designers develop and test color palettes for digital products?

[Kyle30]

I'm a freelance graphic designer working on a branding project for a new wellness app, and I'm stuck trying to choose a color palette that conveys calm and trust but also feels modern and not overly clinical or cliché. I understand the basics of color theory, but applying it to digital interfaces where colors interact with screen light is different from print. For other UI/UX or brand designers, how do you develop and test color palettes for digital products, especially when considering accessibility standards and the psychological impact of colors across different cultures and contexts?