The data system the sink connector is connecting to should be in the same region as your Confluent Cloud cluster. If you use a different region or cloud platform, be aware that you may incur additional data transfer charges. Contact your Confluent account team or Confluent Support if you need to use Confluent Cloud and connect to a data system that is in a different region or on a different cloud platform.
You can create a new cluster in AWS – no need for a separate Confluent Cloud account.
For the sake of completeness, if you procured Confluent Cloud through the Google Cloud Marketplace then you wouldn’t be able to create resources in AWS, but it doesn’t sound like that is the case since you mentioned “free tier”. There isn’t currently an option that Confluent would call a “free tier” so I assume this means that you haven’t entered a payment method and are using credits.