Right way to use a constructor to set interfaces address?

Smart Contracts
1

No really a problem, just need to understand a few things :

With this piece of code, transaction is reverted when calling "getEstimatedTokenForBNB" function.

// Initialize Parameters

constructor () {

    tokenAddress = 0xf63DB3cc676b71F8D38D27181d0AE9d7Aa4F1D48;
    wbnbAddress = 0xae13d989daC2f0dEbFf460aC112a837C89BAa7cd;
    pairAddress = 0xD280a7D55faa4a982616e8d5C6b2D68B5Ce366aF;
    routerAddress = 0x9Ac64Cc6e4415144C455BD8E4837Fea55603e5c3;
    userManagementAddress = 0xa1eD4f05cE96241e75817765c78eFAA74a9c120C;
}

// Initialize Interfaces

IUserManagement USERMANAGEMENT = IUserManagement(tokenAddress);
IDEXRouter iROUTER = IDEXRouter(routerAddress);
IBEP20 TOKEN = IBEP20(tokenAddress);  
IBEP20 LPTOKEN = IBEP20(pairAddress);
IBEP20 WBNB = IBEP20(wbnbAddress);

// Modifiers 

modifier onlyToken() {
    require(msg.sender == tokenAddress); _;
}

// View Functions


function getEstimatedTokenForBNB(uint buyAmountInWei) public view  returns (uint[] memory) {

    uint[] memory bnbQuote;
    bnbQuote = iROUTER.getAmountsOut(buyAmountInWei, getPathForWBNBToToken());
    return bnbQuote;
}

// Utility Functions

receive() external payable {}

function getPathForWBNBToToken() public view returns (address[] memory) {
    address[] memory path = new address[](2);
    path[0] = wbnbAddress;
    path[1] = tokenAddress;
    
    return path;
}

function checkAmountValidity (uint buyAmountInWei) public view returns(bool checkResult) {
    try iROUTER.getAmountsOut(buyAmountInWei, getPathForWBNBToToken()) {
        checkResult = true;
        return checkResult;        
        }
    catch {
        checkResult = false;
        return checkResult;
        }
}

I found that if I set manually addresses in the // initialize Interfaces section, everything works as expected.. so I suppose that my constructor doesn't set the parameters at time.

Anyone can explain me the right way to proceed ? I don't understand why constructor doesn't work..