Implement Func<T,TResult> delegate in Typescript

Question

Fairly new to the node ecosystem and Typescript. I am looking for how to implement an abstract delegate Func<T,TResult> in Typescript.

A C# Example of what I want to do:

A ProxyClient for an API integration.

public interface IProxyClient
{
    Task<TResult> GetData<TInput,TResult>(TInput input);
    Task<TResult> AnotherOperation<TInput,TResult>(TInput input);
}

A "worker" class that will do stuff - including make the call to the API endpoint.

public abstract class Manager<TInput,TResult>
{
    private readonly IProxyClient _proxyClient;
    
    protected abstract Func<IProxyClient,TInput, Task<TResult>> proxyClientDelegate { get; }

    public async Task<TResult> DoAThing(TInput input)
    {
        var result = await proxyClientDelegate.Invoke(_proxyClient, input);
        //... Do Some other stuff
        return result;
    }
}

Derived classes of the manager would implement the actual method call:

public sealed class DerivedManager : Manager<InputClass, OutputClass>
{
    protected override Func<IProxyClient, InputClass, Task<OutputClass>> proxyClientDelegate =>
        (client, input) => client.GetData<InputClass, OutputClass>(input);
}

public class AnotherDerivedManager: Manager<SomeOtherInputClass,SomeOtherOutputClass>
{
    protected override Func<IProxyClient, SomeOtherInputClass, Task<SomeOtherOutputClass>> proxyClientDelegate =>
        (client, input) => client.AnotherOperation<SomeOtherInputClass, SomeOtherOutputClass>(input);
}

Allows for the abstraction in each derived manager.

public class Program
{
    private readonly DerivedManager _derivedManager;
    private readonly AnotherDerivedManager _anotherDerivedManager;

    public Program(DerivedManager derivedManager, AnotherDerivedManager anotherDerivedManager)
    {
        _derivedManager = derivedManager;
        _anotherDerivedManager = anotherDerivedManager;
    }

    public async Task Execute()
    {
        var inputClass = new InputClass();
        var outputClass = await _derivedManager.DoAThing(inputClass);

        var anotherInputClass = new SomeOtherInputClass();
        var someOtherOutputClass = await _anotherDerivedManager.DoAThing(anotherInputClass);
    }
}

How would I do this in typescript (is it even possible).

UPDATE: I found a solution. Will post the answer with examples shortly.