AWS access as company owner

Solution 1:

I would expect the process to be similar to what AWS documents for recovering access in case of a regular employee with administrator access that has left the company. See:

https://aws.amazon.com/premiumsupport/knowledge-center/admin-left-need-acct-access/

The simplest way to get the credentials for the account is to ask the former administrator of the account.

If that's not possible, try the following:

If the email address is associated with a corporate domain ... contact your email administrator to discuss options that can help you gain access to the email address. Ask your email administrator if they can give you access to the email address, or pass along a password reset email for the account.
...

If you have root access to the account, but don't know the password for a particular IAM user, sign in as the root user, and then change the password.
Important: AWS Support can't change the root or IAM credentials on an account for any reason.

That of-course assumes that a corporate e-mail address was used to set up the company AWS account. If a personal e-mail account was used that approach won't work.

And related:

https://aws.amazon.com/premiumsupport/knowledge-center/transfer-aws-account/