Unity 3D Application Architecture for the Olympiad. How is it better?

Question

Game development

Hello!
Help, please, to determine the "compromise" architecture of the solution (technologies, tools, infrastructure) based on Unity3D, taking into account the limitations. Is the choice of Unity3D optimal for this task? If so, what is the best way to build the architecture?
General task: Within the framework of the social. initiatives, we want to make the Olympiad in programming for schoolchildren, in a playful way, so that the event would be more interesting for participants and outside observers.
Limitations:
We were inspired by resources such as www.codingame.com and 2012.russianaicup.ru.Our schoolchildren do not speak English at a sufficient level and I want to make the application more spectacular, on Unity 3D, when the initial tasks are possible in single-user mode, and in the final, it will be possible to launch a multiplayer game so that the code (algorithm) of the participants participates in the game - battle. The event takes place offline, with the meeting of participants. We are not Mrs. organization, but a group of enthusiasts, and I want to "save" on development and thereby increase the prize fund, if possible. By saving I mean, among other things, the optimal architecture of the solution, where there will be no heavy (expensive infrastructure) server (cloud) solutions, and for example, one of the computers can be used as a server for the final, multiplayer battles in the game, and at the initial single-player stages,
The complexity of the task is that the Unity application could accept and process the code written by the participant. Embedding such a mechanism in the Unity application itself is probably difficult and expensive, but perhaps there are better alternatives?
Software part, as an option
The game is made in Unity 3D and acts as a server that exchanges information via API with clients through standard network interfaces (HTTP, TCP / IP, etc.). Clients are any programs that can send commands to the interface (API) of the game/server.
Preliminary TOR at the link: https://docs.google.com/document/d/17iapBTbAy55ax5...
Thank you in advance!

Answer 1

We are not Mrs. organization, but a group of enthusiasts, and I want to "save" on development

And why do you need development? What, many times like this it was possible, without experience, to solve such issues?
Look for ready-made (or semi-finished) solutions on github.