WhereScape RED - Azure SQL Support
RED does support Azure SQL family for the WS RED Metadata Repository and DWH Target but there are limitations with some of the Azure SQL offerings:

Azure SQL DB (limited RED functionality)
Azure SQL MI (untested but is supposedly 100% compliant with SQL Server instance so should work fine with full RED functionality)
    SQL Server on Azure VMs (full RED functionality supported)

Azure SQL DB limitations
Loading data to Azure SQL DB:
Only SSIS Load and ODBC Load are supported on Azure SQL
Workaround: for other load types is to write your own script based templates.
Future support: Full template support via a new Azure SQL DB Enablement Pack for RED is expected to be released in CY21Q4

RED Backup/Restore on Azure SQL DB
Unload/Load the Metadata to/from Disk - not supported
Export/Restore the Metadata (SqlServer BCP) - does work but only with certain authentication types.

RED Generated Update procedures
RED generated Update Procedures call various RED Metadata Procedures as a part of the auditing and logging process, due to this architecture and the limitation of Azure SQL DB not having cross db support we only support RED Metadata and your Azure SQL DB data warehouse target in the same Azure SQL DB, they can be in separate schemas though.

Multi-Database SQL is not supported on Azure SQL DB
We can only support RED Metadata and your target DWH on the same database due to the Azure SQL DB not supporting cross database connectivity. They may be on separate schemas though.
Workaround: Write your own script based templates.
Future support: Full template support via a new Azure SQL DB Enablement Pack for RED is expected to be released in CY21Q4

Azure SQL DB as a repository only (using a WS Target Enablement Pack)
If you only use Azure SQL DB as the RED metadata repository and you are using a WhereScape Target Enablement Pack for one of our supported data warehouse targets then most of the limitations mentioned above are not an issue since the Enablement Packs are script based templates which deal with the metadata, sources and targets in separate odbc or native tooling calls.