How to test code with Jest that uses readonly properties of mocked dependencies?

I want to unit test this TS code with Jest:

MyClass.ts

import Dependency from "./Dependency";

export default class MyClass {
    public constructor(private dependency: Dependency) {}

    public DoIt(): string {
        return this.dependency.MyProp;
    }
}

It uses this class:

export default class Dependency {
    public get MyProp(): string {
        return "A string";
    }
}

This is my test so far:

import MyClass from "./MyClass";
import Dependency from "./Dependency";

jest.mock("./Dependency"); // Here we do auto mocking

it("connects with the server for match info messages", () => {
    // Arrange
    const dependency = new Dependency();
    const sut = new MyClass(dependency);
    // dependency.MyProp = "Another string"; // Cannot assign to 'MyProp' because it is a read-only property.ts(2540)
    jest.spyOn(dependency, "MyProp", "get").mockReturnValueOnce("Another string"); // Error: MyProp property does not exist

    // Act
    const retval = sut.DoIt();

    // Assert
    expect(retval).toStrictEqual("Another string");
});

As noted in the comments, I can’t properly mock the MyProp property. At runtime, it’s undefined because auto mocking doesn’t see it as a function so it ignored it.

Question: How to properly mock public properties on mocks without giving up auto mocking?