PyQt window closes immediately (but not in debug mode)

Question

I am working on a project in PyQT5

My logic was:

If pushButton (Login button) is pressed

Navigate to WelcomeScreen

The issue is as soon as I press login button, I can see something open for extremely brief moment. Windows gets closed but program is still running

But, Weirdly enough, when I debug the code, the Welcome Screen opens without any issue.

Before asking this question, I made sure I searched for possible solutions. I've tried few such as returning myWelcomewin in open_welcome_screen method as specified here PyQt window closes immediately after opening

P.S: I am working in PyCharm.

Code:

import sys

from PyQt5.QtCore import QTimer
from PyQt5.uic import loadUi
from frontend import WelcomeScreen
from LoginForm import Ui_SVA
from WelcomeScreen import Ui_WelcomeScreen
from PyQt5.QtWidgets import QMainWindow, QApplication, QDialog
import os
from os import path
import sqlite3

class WelcomeWindow(QDialog, Ui_WelcomeScreen):
    def __init__(self):
        super(WelcomeWindow, self).__init__()
        loadUi('WelcomeScreen.ui', self)

class MainWindow(QDialog, Ui_SVA):
    def __init__(self):
        super(MainWindow, self).__init__()
        loadUi('LoginForm.ui', self)

        # Connect button clicked signal to slot
        self.pushButton.clicked.connect(self.open_welcome_screen)

    def open_welcome_screen(self):
        # Hide the login screen
        self.hide()
        myWelcomewin = WelcomeWindow()
        myWelcomewin.show()
        myWelcomewin.raise_()
        


if __name__ == '__main__':
    app = QApplication(sys.argv)
    myWin = MainWindow()
    myWin.show()
    sys.exit(app.exec_())