It will be really easy to solve your problem with the library I created. It is called Atributika.
let calculatedCoffee: Int = 768
let g = Style("g").font(.boldSystemFont(ofSize: 12)).foregroundColor(.red)
let all = Style.font(.systemFont(ofSize: 12))
let str = "\(calculatedCoffee)<g>g</g>".style(tags: g)
.styleAll(all)
.attributedString
label.attributedText = str
You can find it here https://github.com/psharanda/Atributika