How do I overload a TSet<struct> == operator?

Hi there. This is the code I am using:

TSet<TSet<Fpiece>> ply; //empty
TSet<Fpiece> p; // populated
TSet<FPiece> k;
for(auto x : p) k.Add(x);
ply.Add(k);

I have already overloaded the GetTypeHash function, however, when I compile in UE5 I get the error:
error C2678: binary '==': no operator found which takes a left-hand operand of type 'const T'
How do I resolve this?

OK so simple workaround. I changed TSet<TSet<Fpiece>> to std::list<TSet<Fpiece>> and it compiled. Don’t know if I will get the same performance as I would with a TSet but we will see.