Getting and passing an encrypted password between Flask, Ansible, then back to Python using Fernet

Question

I am currently creating a web application with Flask.

My Flask Python gets a password from user input through a webform, then that password is pushed to Ansible using the ansible_runner module.

form.py

from cryptography.fernet import Fernet
from tools import load_key
from ansiblerunner import ansible, inventory_hosts

ansible_role = "role"
tags = "install"

username = request.form.get("username")
dcryptpwd = request.form.get("password")

# Encrypt encpwd to pass to Ansible
refKey = load_key()
key = Fernet(refKey)
pwdbyt = bytes(dcryptpwd, 'utf-8')
encpwdbyt = (key.encrypt(pwdbyt))
encpwd = encpwdbyt.decode('utf-8')

inventory = inventory_hosts(username)
runner = ansible(hostname, ansible_role, encpwd, tags)

return render_template("form/form.html")

tools.py

def load_key():
    with open('refKey.txt') as f:
        refKey = ''.join(f.readlines())
        refKeybyt = bytes(refKey, 'utf-8')
        f.close()
    return refKeybyt

Ansible is then using it on my role in main.yml

- block:
  - name: Run setup.py
    command: "{{ setup_py_run }} --username {{ username }} --encpwd {{ encpwd }}
    no_log: false
  delegate_to: localhost
  tags: 
    - rebuild

Then setup.py decrypts the password and uses it here:

# Arguments imported from ansible
username = args.username
encpwd = bytes(args.encpwd,'utf-8')

# Decrypt password
refKey = load_key()
key = Fernet(refKey)
encpwdbyt = key.decrypt(encpwd)
password = encpwdbyt.decode('utf-8')

Currently this solution works, in the Ansible logs the plaintext password no longer shows up and the password gets decrypted successfully.

A few questions here:

1. As this stands the private key is hidden in my server in a random directory, and the server is protected with SSH keys. Is this a secure way of 'hiding' a private key?
2. Instead of having one key stored that encrypts and decrypts, would it be more secure to generate a new key each time, overwriting the previous key used?
3. Is encryption even necessary or am I overthinking this? Should obfuscation be used instead?

I am new to programming and even newer to program security, any insight would be greatly appreciated, thank you!