Which OAuth2 for Internal Server App?

I'm new to CC Api.

I'll looking to connect our internal web-app to Constant Contact data using the api.

Our web-app will be running cron jobs from our server...so login page prompts are not possible.

The application process is asking me to choose:

• Authorization Code Flow and Implicit Flow
• Proof Key for Code Exchange (PKCE) Flow
• Device Authorization Flow

And:

• Rotating Refresh Tokens
• Long Lived Refresh Tokens

I will be using cron jobs to periodically pull data from the cc api.

Which of the methods listed above is most suitable for this?

Thanks