Emulating Polymorphism without virtual pointers/overhead

Question

Before reading I must emphasise I have demanding performance requirements (not premature optimization- processing millions of messages and need to design with performance in mind from the beginning). If I didn't have these requirements I would just use polymorphism.

I am using C++17 and have ~30 different classes/types. Each class uses CRTP to inherit from a Base and has three identical methods:

template<class D>
struct Base
{
    // Shared behaviour
}

struct ObjectN : public Base<ObjectN>
{
    void doA(int p);
    void doB(int p);
    void doC(int p);
};

Because I am avoiding Polymorphism I just declare the 30 types manually:

Object1 _object1;
.
.
Object30 _object30;

Currently I have 3 wrapper methods to invoke the 3 methods across the 30 classes, switching on the object type and invoking the relevant object's method (doA(), doB() or doC()):

void callDoA(int object_type)
{
    switch(object_type)
    {
        case Object1:
            _object1.doA();
            break;
        case Object2:
            _object2.doA();
        .
        .
        case Object30:
            _object30.doA();
    }
}

void callDoB(int object_type)
{
    switch(object_type)
    {
        case Object1:
            _object1.doB();
            break;
        case Object2:
            _object2.doB();
        .
        .
        case Object30:
            _object30.doB();
    }
}

void callDoC(int object_type)
{
    switch(object_type)
    {
        case Object1:
            _object1.doC();
            break;
        case Object2:
            _object2.doC();
        .
        .
        case Object30:
            _object30.doC();
    }
}

With 30 x 3 case labels this is not good. The design doesn't feel right.

Given the switch statements are effectively identical (except the method called) is there a smarter way I could do this? I was thinking of re-using the switch statement and passing something in? My first though was a lambda but I'm concerned about performance. However, I can't have 90 case labels!

I could put the 30 types within a variant if helps provide a solution?