Secondly, according to the MS documentation from here Resource naming restrictions - Azure Resource Manager | Microsoft Learn
Resource and resource group names are case-insensitive unless specifically noted in the valid characters column.
When using various APIs to retrieve the name for a resource or resource group, the returned value may have different casing than what you originally specified for the name. The returned value may even display different case values than what is listed in the valid characters table.
Always perform a case-insensitive comparison of names.
And for the specifics of Resource Groups