How to programmatically add root folder to the path for every script?

The file structure I currently have is something like:

__init__.py
script_folder
    __init__.py
    s1.py
    s2.py
b_folder
    __init__.py
    b1.py
    b2.py
lib_folder
    __init__.py
    lib1.py
    libb2.py

Files in b_folder can use the files from lib_folder, and the scripts in script_folder can use the files from b_folder and lib_folder. I do imports as follows:

from lib_folder.lib1 import func_1

Imports from other folders seem to work if I add

import sys; sys.path.insert(0, '.') 

to every single file that does an import from another folder. Like this, it all works. But this repetitive line pollutes my code.

I wonder if there is a way to add the root folder to the path project-wide, or directory-wide, without having to add any magic line to every file that needs to import something from another folder?

Changing $PATH on my computer is not a good solution for me because the code is supposed to run on other machines.

I have tried to add import sys; sys.path.insert(0, '.') to all __init__.py, but it does not seem to make any difference.

My launch.json (in Visual Studio Code) is as below:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Python: Current File",
            "type": "python",
            "request": "launch",
            "program": "${file}",
            "args": ["-m"],
            "console": "integratedTerminal",
            "justMyCode": true
        }
    ]
}