Not paying a debt and walking away isn't a criminal offence.

Signing up again under a different name to continue using the service you have been banned from could be considered fraud by misrepresentation, which in most places is a fairly serious criminal offence (even though it is very unlikely to be prosecuted in this case).

Cybercrime aside, AWS is almost always not worthwhile for small business or individual use. Issues like opaque billing, devops complexity and vendor lock-in go away immediately if you switch to Digital Ocean or one of the many simpler and cheaper cloud providers. Unless you are building something that is specific to AWS, relying on AWS as individual/small company is like buying enterprise router from Cisco or Fortinet for your home network - technically nothing is stopping you from doing so, but it's an overkill.