Looking for the perfect stack

We are looking for some advice for a project we’re currently working on. We are making a platform that consists of a website/webapp and mobile app.

The landingpage/homepage is pretty basic with some information, images and a video about our platform. Next on we want to make a chatbot on a second page. This is also the start of the registration form. The bot will ask the user his name and email and some questions about their proces. After the conversation, all the data has to be send to a database. We’ll need to analyse this data and if that is finished, we need to send an email with the results to the user.

If the user is interested for our platform he can subscribe and make a payment. If the payment is accepted he’ll have access to a private part on the website and our mobile app. The biggest part of this private part is a course. Every week the user will get access to a new chapter. Besides that he has to fill in some questions about his proces. This is a daily task and the results can be viewed in different charts.

In the future everything will be in multiple languages.

I doubt which stack I should use. Currently it’s React, Mobx, Firebase but that’s more for a web app only? Is it ok to put the whole homepage and course in Firebase?