A way to retrieve reports will be available in 2023 R2. You can see the release notes for 2023 R2 Beta for details: Acumatica 2023 R2 Beta 2 Developer Release Notes (Web Services: Retrieval of Reports Through the REST API)
There is the option to send an email from a SalesOrder (ScreenId: SO301000). The email is being created and an attachment is generated. We want to retrieve/download this specific attachment (Files) programmatically.
A way to retrieve reports will be available in 2023 R2. You can see the release notes for 2023 R2 Beta for details: Acumatica 2023 R2 Beta 2 Developer Release Notes (Web Services: Retrieval of Reports Through the REST API)