can I indicate Textract to find only digits in a given image?

Thank you for using Amazon Textract.

Unfortunately we don't have an API to detect only digits from an image. You can parse the full response to extract texts with only digits. Hope below links could help you.

1. Lib for parsing Textract response and extract interested fields - https://github.com/aws-samples/amazon-textract-response-parser
2. How to parse Block object - https://docs.aws.amazon.com/textract/latest/dg/API_Block.html

For issues like, 5 detected as S and more similar problems, we are continuously improving the quality of our models and releasing new features as a managed machine learning service. In order to help us improve our models for your documents, please open a customer support ticket and share details to help us analyze further. Additionally, please look out for announcements regarding our model quality updates and new feature announcements that are announced on the AWS Textract what’s new post channel.

Yes you can ..please refer to partner blog where Data is extracted form the IDs using textract

https://aws.amazon.com/blogs/apn/automating-the-know-your-customer-process-using-capgemini-ai-powered-solution-on-aws/