There was a workaround to add #{Number} (e.g. #1) to the end of the Identifier (Entity ID).
The following is an example for AWS.
https://github.com/MicrosoftDocs/azure-docs/issues/57571
> Adding "#" and followed by a unique number is required only when there are multiple instances of Amazon Web Services (AWS) enterprise application added to the same Azure AD tenant.
I'm interested in MSP-specific considerations. This topic is nice.