Personal account - means of implementation?

Question

Backend

Good afternoon!
I have not asked questions here for a very long time, I am extremely glad that the resource is developing. :)
To the point, I'm still not connected with programming (in any form), but I'm still interested in it with some frequency, now I'm thinking over one project, I will look for performers, but the advice is interesting:
We need to implement a "portal", with the ability to authorization (session, etc), downloading files, working with a large amount of data, making many entries by many users, a conditionally loaded personal account.
Interested in performance, load on the server side, database protection.
What is better as a main implementation tool - PhP or JS and why? For example (just an example): php works worse with uploaded files, js is full of holes in terms of leaks from the database. I want to try to understand the pros and cons before writing TK.
Functionality (in short):
The administrator creates a user (registration is not needed), the user enters the logopass (a session is assigned), fills in the tables, uploads the necessary files. The necessary api (zakupki.gov.ru, kontur, spark, fiscal, arbitration and other state resources) pick up the data entered by the user and give the final result to another group of users.
Subject - state order.
Any ideas?
PS
If the question is stupidly asked - correct me, I'll try to clarify something.

Answer 1

InfernalOwl ,
"As if there was a question - I want to write a program to control a ballistic missile, which is better - Java or Assembler? To which they would answer that Java is slow for this task, Assembler is fast. This was an example of such an answer, "in theory" . "
In this case, you do not need to choose a language, but physicists-mathematicians who can calculate the formula for you. And programs for such calculations are ALREADY written.
I advise you not to choose tools (programming languages ​​and technologies) but to write technical specifications for the result.
Leave the choice of technologies to qualified personnel - to the same contractor.
If you wish, you can add a clause to the TOR that the choice of technologies should be argued and agreed with you before starting work.
In a normal large project, the preparation of the project itself (TOR) is a separate huge part of the work, which can take up to a third of the time or even more.

Answer 2

php works worse with loaded
js files leaky in terms of leaks from the database
I foresee you write any heresy in TK.
Hire a specialist who is well versed in the technical part and drafting technical specifications.

Answer 3

You won't get a definitive answer. An unambiguous answer can only be given by a developer who will delve into the technical specifications and be able to understand what technologies the front uses, then you can understand what should be on the back.
working with files, vulnerabilities, etc. depend on the crooked hands of the programmer, not the tool. Yes, in each specific case, either js or php or some other PL will be justified. But so far there is no specific case. According to your short information, only those who know only 1 of them will give answers in favor of a particular language.