Etherscan Shows Token TotalSupply with all 18 Decimals. Why?

Question

I just deployed the token smart contract and Etherscan shows the TotalSupply with all 18 decimals for some reason. Basically, it shows excessive 18 zeroes in the TotalSupply section. Could you please explain what's wrong with the code, which is very simple? Please see attached and thank you in advance!

pragma solidity ^0.8.17;
///SPDX-License-Identifier: MIT
    
abstract contract EIP20Interface {
    // total amount of tokens
    uint256 public totalSupply;

    // @param _owner The address from which the balance will be retrieved
    // @return The balance
    function balanceOf(address _owner) virtual public view returns (uint256 balance);

    // @notice send `_value` token to `_to` from `msg.sender`
    // @param _to The address of the recipient
    // @param _value The amount of token to be transferred
    // @return Whether the transfer was successful or not
    function transfer(address _to, uint256 _value) virtual public returns (bool success);

    // @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
    // @param _from The address of the sender
    // @param _to The address of the recipient
    // @param _value The amount of token to be transferred
    // @return Whether the transfer was successful or not
    function transferFrom(address _from, address _to, uint256 _value) virtual public returns (bool success);

    // @notice `msg.sender` approves `_spender` to spend `_value` tokens
    // @param _spender The address of the account able to transfer the tokens
    // @param _value The amount of tokens to be approved for transfer
    // @return Whether the approval was successful or not
    function approve(address _spender, uint256 _value) virtual public returns (bool success);

    // @param _owner The address of the account owning tokens
    // @param _spender The address of the account able to transfer the tokens
    // @return Amount of remaining tokens allowed to spent
    function allowance(address _owner, address _spender) virtual public view returns (uint256 remaining);
  
      // solhint-disable-next-line no-simple-event-func-name
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}



pragma solidity ^0.8.17;
///SPDX-License-Identifier: MIT

import "./EIP20Interface.sol";

contract XXXXX is EIP20Interface {

    uint256 constant private MAX_UINT256 = 2**256 - 1;
    mapping (address => uint256) public balances;
    mapping (address => mapping (address => uint256)) public allowed;

    string public name;                   
    uint8 public decimals;                
    string public symbol;                 

    constructor(
        uint256 _initialAmount,
        string memory _tokenName,
        uint8 _decimalUnits,
        string memory _tokenSymbol
    ) public {
        balances[msg.sender] = _initialAmount;               
        totalSupply = _initialAmount;                        
        name = _tokenName;                                   
        decimals = _decimalUnits;                            
        symbol = _tokenSymbol;                               
    }
    function transfer(address _to, uint256 _value) override public returns (bool success) {
        require(balances[msg.sender] >= _value);
        balances[msg.sender] -= _value;
        balances[_to] += _value;
        emit Transfer(msg.sender, _to, _value); //solhint-disable-line indent, no-unused-vars
        return true;
    }
    function transferFrom(address _from, address _to, uint256 _value) override public returns (bool success) {
        uint256 allowance = allowed[_from][msg.sender];
        require(balances[_from] >= _value && allowance >= _value);
        balances[_to] += _value;
        balances[_from] -= _value;
        if (allowance < MAX_UINT256) {
            allowed[_from][msg.sender] -= _value;
        }
        emit Transfer(_from, _to, _value); //solhint-disable-line indent, no-unused-vars
        return true;
    }
    function balanceOf(address _owner) override public view returns (uint256 balance) {
        return balances[_owner];
    }
    function approve(address _spender, uint256 _value) override public returns (bool success) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value); //solhint-disable-line indent, no-unused-vars
        return true;
    }
    function allowance(address _owner, address _spender) override public view returns (uint256 remaining) {
        return allowed[_owner][_spender];
    }
}