How to create a customized login page that logs in to Odoo?

I am working on Odoo 14 Community Edition.

I would like to create a customized login page (I already know how to create a login page). However, what I need to know are:

1. How can I connect this customized login page to the Odoo system? The customized login page will have all of the required information that Odoo needs. I know I need to call an API or redirect to a URL, but which one?
2. How to configure Odoo to display my customized page as the login landing page instead of the default one?

I know there are 2 questions here but with only either one of these two the main question cannot be solved.

In order to render your custom login page instead of default one, either you will have to modify the odoo controller which renders the template or modify the template which is rendered using the controller.

The controller is:

@http.route('/web/login', type='http', auth="none")

And the template is:

<template id="web.login" name="Login">