Simple Monad Design Pattern in C#

1_Monad.cs

public class Monad<TValue>
{
    private readonly TValue? _value;

    public Monad(TValue? value)
        => this._value = value;

    public Monad<TResult?> AnyWay<TResult>(in Func<TValue?, TResult?> func)
        => new(func(this._value));

    public Monad<TValue?> AnyWay(in Action<TValue?> func)
    {
        func(this._value);
        return this;
    }

    public Monad<TResult?> NotNull<TResult>(in Func<TValue, TResult?> func)
        => this._value is not null ? new(func(this._value)) : new(default);

    public Monad<TValue?> NotNull(in Action<TValue> func)
    {
        if (this._value is not null)
        {
            func(this._value);
        }

        return this;
    }
}

2_program.cs

var p = new Person("Ali", 5);
var maybe = new Monad<Person>(p)
                .NotNull(p => new Person("Reza", 5))
                .AnyWay(p => WriteLine($"p: {p}"))
                .NotNull(_ => (Person?)null)
                .AnyWay(p => WriteLine($"p: {p}"));