If you're looking for music with an "embers" aesthetic or theme, you may want to try searching for music that features warm or smoky tones, such as music with a lot of brass or woodwind instruments, or music that has a slow and sultry feel.
As for an "embers" background, you could try searching for images or videos of fire, embers, or glowing coals. You may also want to look for images or videos with warm, orange and red tones that evoke the feeling of heat.
Keep in mind that music and imagery can be subjective, so what one person considers to have an "embers" aesthetic may not be the same for another person. It may be helpful to experiment with different types of music and imagery until you find what works best for your needs.
