FileNotFoundError despite file existing

This is the function that uses a file to return some parameters

def load_network_params(agent_name: str, env_name: str,
                        network_root_folder: str = 'jax-models') -> flax.core.FrozenDict:

    filePathString=network_root_folder+r"/"+agent_name+r"/"+env_name+r"/2"
    fileNameStr=r"ckpt.199"
    fileString=os.path.join(filePathString,fileNameStr)
    with open(fileString, 'rb') as file:
     # file processing irrelevant to error
        })
    return network_params

This is the way the function was subsequently used:

from dataset import *
generate_dataset(r"dqn", r"Breakout", 10_000, network_root_folder=r"C:/Users/jk5g19/Documents/Year3IP/scripts/jax")

Edit: Basically the generate_dataset calls load_network_parameter, I tried to cut down the amount of code shared, so that people would get less confused. This is the Minimum Viable product.

def generate_dataset(agent_name: str, env_name: str, dataset_size: int, num_envs: int = 20, epsilon: float = 0.1,
                     network_root_folder: str = 'jax-models') -> Tuple[onp.ndarray, onp.ndarray, onp.ndarray,
                                                                       onp.ndarray, int]:

    num_actions = gym.make(f'{env_name}NoFrameskip-v0').action_space.n

    images_obs_dataset = onp.zeros((dataset_size, 84, 84, 4))
    ram_obs_dataset = onp.zeros((dataset_size, 128))
    q_values_dataset = onp.zeros((dataset_size, num_actions))
    action_dataset = onp.zeros(dataset_size)

    network_def, network_args = get_network_def(agent_name, num_actions)
    network_params = load_network_params(agent_name, env_name, network_root_folder=network_root_folder)

    return images_obs_dataset, ram_obs_dataset, q_values_dataset, action_dataset, episodes_run

When I output the filestring and copy and paste it into the file explorer the desired file can be accessed. I used raw strings for the path and experimented with double back slashes and forward slashes.

I also added a test.txt file in the path too, the file path did not work hence it rules out the file type causing issues with open().

screenshot of error

Turns out that for my dataset_setup.py I was supposed to do this:

from dataset import *
generate_dataset(r"dqn", r"Breakout", 10_000, network_root_folder=r"/mnt/c/Users/jk5g19/Documents/Year3IP/scripts/jax")

This was because I was using WSL. Massive thank you to @gionni for helping me come to this conclusion.