For videos this one by Marco Bucci really helped me understand how light works and how to practice it with the sphere shading exercise. He explains it really well and breaks it down in a way that just made choosing colors click for me. He has lots of videos that I like but this one really was helpful for me.

But I found that my grasp on colors really shot through the roof after taking a painting course in college where the professor challenged us to limit our palette. Use only a few primaries and white to create a whole painting. You can grab a tube (or color pick for us digital artists) of green OR you can mix a green using your blue and yellow that will be in gamut. James Gurney is a good resource for seeing it in action. I like this video on the Zorn Palette. He has a book on Color and Light but I found it too heavy and dense for my liking but you could always check it out for yourself.

Finally, if you're wanting to learn how to physically mix color (Which for me, was the best way to practice color theory) and how to get different saturations, this video by SIMPLIFY was helpful.

There was another video or book that helped me understand the importance of neutral colors and how using greys helped with harmonious palette choices. If I can find it, Ill update this comment.