Create an overlay, aligning a guide of the reference view to a different guide of the overlaid view.

TwoSidedAlignmentOverlay.swift

extension View {
	@available(iOS 15.0, macOS 12.0, *)
	func overlay<Target: View>(align originAlignment: Alignment, to targetAlignment: Alignment, of target: Target) -> some View {
		let hGuide = HorizontalAlignment(Alignment.TwoSided.self)
		let vGuide = VerticalAlignment(Alignment.TwoSided.self)
		return alignmentGuide(hGuide) {$0[originAlignment.horizontal]}
			.alignmentGuide(vGuide) {$0[originAlignment.vertical]}
			.overlay(alignment: Alignment(horizontal: hGuide, vertical: vGuide)) {
				target
					.alignmentGuide(hGuide) {$0[targetAlignment.horizontal]}
					.alignmentGuide(vGuide) {$0[targetAlignment.vertical]}
			}
	}
}

extension Alignment {
	enum TwoSided: AlignmentID {
		static func defaultValue(in context: ViewDimensions) -> CGFloat { 0 }
	}
}

As a solution for https://stackoverflow.com/questions/68554713/swiftui-reference-the-screen-position-of-another-element-in-the-view/68555127#68555127