Do you have some sort of outline for your game yet?
(Also is this a game surrounding an AU? This may or may not change my answer)

Ohh. Fun!

To start, see if the player wants to play!

play = input('Do you want to play?(Y/N) ')

if play.lower() == 'y':
    pass # next step!
if play.lower() == 'n':
    print('Ok, cya next time!')

Now, if the player puts y:

if play.lower() == 'y':
    user_info = {}
    username = input('Username: ')
    user_info.update({'Username':username,'GameInfo':[]})

The above got the users name.
Now, you continue onward and create what you want!
Example

import os # os.system
if play.lower() == 'y':
    user_info = {}
    username = input('Username: ')
    user_info.update({'Username':username,'GameInfo':[]})
    
    print(f'Welcome, {user_info["Username"]}! Here is the menu!')
    print(('-'*30) + ' !MENU! ' + ('-' * 30))
    
    while True:
        choice = str(input(f'1. New Game\n2. Load old game\n\t3. See your status\n4. Exit\n\n> '))

        if choice == '1':
            os.system('clear')
            print(('-'*30) + ' !NEW GAME! ' + ('-'*30))
            # code here to do things for a new game
        if choice == '2':
            os.system('clear')
            print(('-'*30) + ' !LOAD GAME! ' + ('-'*30))
            # code here to do things to load a game
        if choice == '3':
            os.system('clear')
            print(('-'*30) + ' !STATUS! ' + ('-'*30))
            # code here to gather user status from the user_info dict
        if choice == '4':
            os.system('clear')
            print(('-'*30) + ' Ok, cya ' + ('-'*30))
            exit()

I don't usually do this type of stuff..but ye :D

Input

I guess make an input to ask the player if they want to play or not.

play = input("want to play?")
if play == "yes":
  print("cool")
  # start your code to make the undertake
else:
  print("ok")
  # it will just break here

Correct me if I'm wrong about your question