CryptographyDeprecationWarning Python 2 RV

On RV start-up error message
CryptographyDeprecationWarning: Python 2 is no longer supported by the Python core team. Support for it is now deprecated in cryptography, and will be removed in a future release.
from cryptography.fernet import Fernet

RV should use Python 3, you need to change the environment variable.
Change the environment variable to Python 3 for RV
Setting global environment variables on Windows

Note: Starting with the upcoming RV 2022 release, Python 3 will be the default.

See Chapter 4 - Python for more details.