Comment by danbars

Maintaining integration code is hard, no matter how you turn this. Even with your approach, you're still going to have to update your code every time Mailchimp, for example, are updating their API. If integrations is not the business you're trying to compete in, I truly think that you should use an automation platform. There are many to choose from. Use Make or Pabbly as reasonably priced options, or even n8n self-hosted if you need internal automations only.