Refactor platform-dependent paths for cross platform compatibility

[maciejmajek]

Is your feature request related to a problem? Please describe.
The current codebase contains several instances of platform-dependent file paths, which can cause issues when running the software on different operating systems. This lack of cross-platform compatibility may lead to errors and inconsistent behavior across different environments.

Describe the solution you'd like
We should refactor the code to use platform-independent path handling. This can be achieved by:

1. Using Python's pathlib module instead of string concatenation for file paths.
2. Replacing hardcoded path separators with os.path.join() or pathlib.Path.joinpath().

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context