Can't use any methods of an istance of a third-party modules [chess.js] (ELECTRON - preload.js & render.js problem)

Today i faced this problem: i was trying to create a chessboard app (with Electron) using the chess.js modules and the problems showed quickly... I need to use in my render.js file all methods/features that chess.js offers, such as chess.move(), chess.fen() and so on... But after setting sandbox: false (in webPreferences) and writing this in my preload script (preload.js):

const { contextBridge, ipcRenderer} = require('electron')
contextBridge.exposeInMainWorld(
    'electron',
    {
        //other code

        
        getChess : () => {
            const {Chess} = require('chess.js');
            return chess = new Chess;
        }
    }
)

i am unable to use any the methods (to make things more clearer, i am enable to use the "chess" istance of Chess in my render script, i can log this, and it will show the obj (as expected))
this is my render script (render.js):

//get Chess through preload.js
const chess = window.electron.getChess();

//✅ Working (showing the chess obj)

console.log(chess)


//❌ Not Working   (example  Uncaught TypeError: chess.move is not a function)
     
chess.move('e42')
chess.inCheck()
chess.isAttacked()
chess.load()
chess.clear()
chess.board()
chess.fen()
chess.png() 
//. . .

Probably is something stupid to ask, but it seems to me hard to get through.
chess.js have a lot of methods .fen, .move, .load ... i need a way to include all to my render.
I don't wanna set nodeIntegration: true due to security reason.

idk if it will help but here is my main.js file :

const { app, BrowserWindow, Menu, ipcMain} = require('electron')
const path = require('path')
const ipc = ipcMain
Menu.setApplicationMenu(false)

const createWindow = () => {
    const win = new BrowserWindow({
        width : 1500,
        height : 900,
        resizable: false,
        titleBarStyle: 'hidden',
        frame: false,
        webPreferences: {
            nodeIntegration: false, // is default value after Electron v5
            contextIsolation: true, // protect against prototype pollution
            enableRemoteModule: false, // turn off remote
            devTools: false,
            sandbox: false,
            preload: path.join(__dirname, 'preload.js'),
        }
    })
    //win.webContents.openDevTools()
    win.loadFile("src/index.html");
    ipc.on('closeAPP', () => {
        win.close()
    })
    ipc.on('minimizeAPP', () => {
        win.minimize()
    })
    ipc.on('maximizeAPP', () => {
        win.maximize()
    })
    
}

app.whenReady().then( () => {
    createWindow()
    app.on('activate', () => {
        if (BrowserWindow.getAllWindows().length === 0) createWindow()
    })
})


app.on('window-all-closed', () => {
    if (process.platform !== 'darwin') app.quit()
})

There is a way to use all the methods ?

This is by design. Electron does not support, supposedly for security reasons, sending "custom classes" over the contextBridge (as per the documentation) and drops all prototype modifications or prototypes of objects other than Object itself.

This is because you're expected to expose only certain functions of which you're sure they cannot do harm to the renderer process and instead do all processing either in preload.js (not recommended) or in the main process and pass values via IPC.

Mind that the latter will also not work for non-standard Objects, thus it would be best to store the Chess objects you'll need in the main process, manipulate them there, and only pass the values required for (ex.) display to the renderer process. How this is done best is explained in Electron's IPC tutorial.