How to implement a service for translating short phrases?

Question

Automation

Good afternoon colleagues!
I would like to ask your opinion about the implementation of the service for the translation of short phrases. Interested in what tools you would implement such a project. The subject area is described below, the link of the current implementation is also at the very end.
Custom use case:
1) The user who wants to translate the text enters the site and enters the required phrase;
2) After entering the phrase, he sees the counted number of words/characters and the cost;
3) Clicks to order, there is a payment procedure through a third-party service;
4) The user receives a notification in the mail;
5) After the translation is completed, the second letter with the translation arrives.
Use case for translator:
1) After paying for the order, a notification with the requested phrase is sent to the mail;
2) The translator sends the translation (I see two ways, I don't know which one is better for implementation)
a. The translator follows a link with a unique token where an input field is available and enters the translation there. If a translation has been added, the input field is no longer available;
b. The translator simply sends the translation as a response to the letter.
First stage:
1) Design/layout of all interfaces;
2) Implementation of the mechanism for counting words / letters in a phrase and matching its price;
3) Connection of the payment system (the whole business process);
4) Setting up mailings for certain events;
5) Processing translations from a translator.
Second turn:
1) creation of a personal account for the user;
2) creation of a personal account for a translator;
3) admin panel;
4) distribution of orders among several translators;
5) search for the user's phrase in existing translations and the ability to buy a cheaper translation;
6) connection of SMS notifications to translators (for urgent orders).
Accordingly, I am interested in what technologies / tools to use to create such a bike. How not to get into trouble with the architecture, so that in the second stage it would not be excruciatingly painful. In general, I want to do something with my own hands, but I don’t know how to approach. Maybe there is some framework on which my tasks are easily superimposed. I'm not attached to the programming language, I'm ready to learn more if it's worth it.
My experience: C ++ with OOP in the first year of the university (I forgot everything), html / css at the level of layout of simple-simple statics, SQL and database design in everyday work. Everything from applied development.
Now everything works in conjunction: WordPress + Ecwid + Yandex Mail + Google Docs. Automation, as you know, is not one hundred percent. Didn't have to program anything. www.inlatin.ru _
Thanks in advance for your replies!