Increment and Decrement counter in solidity and adding stop time to get it

Count.sol

//SPDX-License-Identifier: MIT
pragma solidity 0.8.7;

contract Counter {
    uint public count;
    uint timestop = block.timestamp + 30 seconds;

    //set block.stamp should not be more than 30 seconds
    function add() public {
      require(block.timestamp <= timestop, "your time is up");
      count ++;
    }
   
    function dec() public {
        require(block.timestamp <= timestop, "your time is up");
        count --;
    }

    // returning count value from the state variable that is declared outside the function
     function getCount() public view returns (uint) {
        return count;
    }

    //this will return the timestamp of the function or operation
    function TimeStamp() public view returns (uint e) {
        e = timestop - block.timestamp;
        return e;
    }

    //this will return how many seconds you used when incrementing or decremmenting the count
     function timeReturn() public view returns (uint) {
       return block.timestamp;
    }
}