Resetting AWS Environment

I'm not entirely sure what you mean by AWS environment, but if you're referring to account configuration, you could check this page. If you refer to custom resources you've created, I'm not aware of anything that resets everything automatically, you should trace back and delete what you created.

There is no built-in way to reset an AWS Account to a "factory default". When using AWS services, you might change your Account configuration and/or create various resources like IAM roles or CloudWatch log groups. Additionally, you might change global or regional service configuration (e.g. for AWS Config or Amazon API Gateway). Further more, while using the services, your Account's internal metrics will change. These are the reasons why there is no way to do a factory reset of an AWS account.

Even when you deploy your resources using the IaC approach (AWS CloudFormation or AWS CDK) and then delete the stacks, you still might end up with having some data or configuration that differs from defaults (consider e.g. CloudWatch metrics - you cannot delete them, they expire automatically).

The only way to fully reset everything is to close your existing Account and create a new one.

You could try manually deleting all resources you have created. You can use AWS Tag Editor to find all resources in all regions and then manually delete them. Alternatively, there are third-party open source tools that try to do this in an automated way (offered not by AWS).