What are the limitations applied to AWS Amplify apps for new accounts?

You're correct that there are stricter limitations for new AWS accounts, including for AWS Amplify. While the standard quota for AWS Amplify apps is indeed 25 per region, new accounts often have reduced quotas that are automatically increased over time based on usage.

For new AWS accounts, the initial quota for Amplify apps is typically lower than the standard 25. The exact number isn't publicly specified, but based on your experience, it seems that for your account, the limit may be as low as 1 or 2 apps.

It's important to note that these initial lower quotas are temporary and are designed to help prevent misuse of AWS services. As you continue to use your account and demonstrate legitimate usage, AWS typically increases these quotas automatically over time.

If you need to increase your quota sooner, you can request an increase through the AWS Support Center. However, as you've experienced, these requests may not always be approved immediately for new accounts. AWS evaluates these requests on a case-by-case basis, considering factors such as account age, usage history, and the specific use case.

In the meantime, you might consider consolidating your applications if possible or exploring other AWS services that might meet your needs until your account's quotas are increased. As your account ages and demonstrates consistent, legitimate use, you should see your quotas increase, allowing you to create more Amplify apps.
Sources
AWS Amplify endpoints and quotas - AWS General Reference
AWS service quotas - AWS General Reference