@tarrahopwood I have sent an email to the Wix CRM/Users API Product Manager @ella-bar-or to address this. The APIs are currently incomplete here and are also missing a changePassword capability. You can only change your password at the moment if you are logged out of the site and then invoke the promptForgotPassword() function or use the forgot password link on the standard Wix Login Form.
The CRM and Users backend is non trivial due to the need to maintain a secure user environment but these are basic features that need to be sorted.