Change a SF Symbol size inside a UIButton

You can do it using SymbolConfiguration like in the sample code below:

let largeConfig = UIImage.SymbolConfiguration(pointSize: 140, weight: .bold, scale: .large)
       
let largeBoldDoc = UIImage(systemName: "doc.circle.fill", withConfiguration: largeConfig)

button.setImage(largeBoldDoc, for: .normal)