How do you switch projects on AWS? In GCP it's a dropdown, in AWS it's completely different account (email or IAM or SAML backed) + captcha + MFA every time if not SAML.
AWS SSO [1] negates a lot of that pain, but still won't let you have two accounts open in the same browser window. You can use email/password logins or a SAML source like Active Directory.
[1]: https://aws.amazon.com/single-sign-on/