You could try this approach using a GeometryReader to force the text to be trailing, such as:

struct RightAlignedScrollView: View {
    let text = "12345"
    
    var body: some View {
        GeometryReader { geom in
            ScrollView(.horizontal, showsIndicators: false) {
                HStack {
                    Spacer()
                    Text(text)
                        .multilineTextAlignment(.trailing)
                }
                .padding(.trailing, 10)
                .frame(width: geom.size.width, alignment: .trailing)
            }
        }
        .background(Color.gray.opacity(0.2))
    }
}

The Spacer is not working, because it is inside a ScrollView. Views inside a ScrollView are shown at their ideal size and the ideal size of a Spacer is very small (10 points).

To fix, set .containerRelativeFrame on the HStack, after the padding:

HStack {
    Spacer()
    Text(text)
        .multilineTextAlignment(.trailing)
}
.padding(.trailing, 10)
.containerRelativeFrame(.horizontal, alignment: .trailing) // 👈 HERE

Other suggestions:

• The Spacer can be dropped, since it doesn’t really work. However, this means you will probably want to use .horizontal padding, instead of just .trailing.

• Without the Spacer, the HStack only contains the Text, so the HStack is now redundant. You could drop the HStack too and apply .containerRelativeFrame to the Text instead.

• The .frame on the ScrollView is also redundant, because the ScrollView automatically uses the full width of the display.

• The initializer that you are using for ScrollView is deprecated. To hide the scroll indicators, use the modifier .scrollIndicators instead.

Here is how the example could be modified:

ScrollView(.horizontal) {
    Text(text)
        .multilineTextAlignment(.trailing)
        .padding(.horizontal, 10)
        .containerRelativeFrame(.horizontal, alignment: .trailing)
}
.scrollIndicators(.hidden)
.background(.gray.opacity(0.2))