I want to optimise this code and improve it using advanced C++.

#include <iostream>  template <class T> class LinkedList {   struct Node   {     T data;     Node * next;     Node(T value) : data(value), next(nullptr) {}   };   Node *head;  public:   LinkedList() : head(nullptr) {}   ~LinkedList();   void insert(T);   void printList();   void recursiveReverse()   {     Node *temp = head;     head = recursiveReverse(temp);   } private:   Node* recursiveReverse(Node* head)   {     if(head == nullptr)       return nullptr;      if(head->next == nullptr)       return head;      Node *firstElement = head;     Node *secondElement = firstElement->next;     head = firstElement->next;     firstElement->next = nullptr; //unlink first node     Node *remainingList = recursiveReverse(head);     secondElement->next = firstElement;     return remainingList;   } };  template <class T> void LinkedList<T>::insert(T data) {   Node *node = new Node(data);   Node *tmp = head;   if(tmp == nullptr)   {     head = node;   }   else   {     while(tmp->next != nullptr)     {       tmp = tmp->next;     }     tmp->next = node;   } }  template <class T> void LinkedList<T>::printList() {   Node *node = head;   while(node)   {     std::cout << node->data << " ";     node = node->next;   }   std::cout<<"\n"; } template <class T> LinkedList<T>::~LinkedList() {   Node *tmp = nullptr;   while(head)   {     tmp = head;     head = head->next;     delete tmp;   }   head = nullptr; }  int main() {   LinkedList<int> ll1;   ll1.insert(2);   ll1.insert(3);   ll1.insert(4);   ll1.insert(5);   ll1.insert(6);   ll1.printList();   ll1.recursiveReverse();   ll1.printList(); }