Multithreading or asynchrony?

Question

Python

There is an online game. I create purely for myself, for practice. Written in Python, what is the server, what is the client.
The question is this.
I wanted many players to be able to connect to the same server. (Up to 10,000 players)
What is the best use here? Multithreading or asynchrony?
And how to store player data? How to get access to them? And it is desirable without different DB. That is, using Python.

Answer 1

"Horses people mixed up in a bunch ..."
There are several different subtasks. They need to be divided. And programming separately. By different methods.
Divide your task into separate subtasks and ask separate questions .
If you are not able to do this, if you are not able to decompose questions, then you can quit programming right away.
For decomposition in programming is the most important aspect.
There are only 2 places where you can save data:
In RAM (temporarily)
On disk (permanently)

Answer 2

You can use sql, or you can use python: a dictionary. Key value than not DB? I don't remember, but the csv format seems to fit.