Cost difference of delegatecall with returned value or mutex

test.sol

pragma solidity 0.8.7;

interface IE {
  function setN() external;
}

contract D {
  uint public n;
  uint private temp;

  function delegatecallSetN(address _e) external { // 23347 
    _e.delegatecall(abi.encodeWithSelector(IE.setN.selector));
    n = temp;
    delete temp;
  }
}

contract E {
  uint public n;
  uint private temp;

  function setN() external {
    temp = 4;
  }
}

// -----------------------------------------------------

interface IG {
  function setN() external returns(uint);
}

contract F {
  uint public n;

  function delegatecallSetN(address _e) external { // 54156
   (bool success, bytes memory returnedData) = _e.delegatecall(abi.encodeWithSelector(IG.setN.selector));
   n = abi.decode(returnedData, (uint));
  }
}

contract G {  
  function setN() external returns(uint){
    return 4;
  }
}