Expenses chart component [Parcel/SASS/BEM]

Hi, I need some help to improve my code, please. I used vanilla JS to complete this challenge and no libraries like chart.js, my issue is that my logic to change the bar color depending on the day of the week works. But it's impractical, I know there's a way to improve it but I was stuck for a couple of days with it. Any help would be amazing!