You're trying to create a Custom CDS view with calculated columns but CDS view gives you some warning messages and because of that you're not able to Publish CDS view.
Warning message: Field XXXX ignored: Data type XXXX not allowed for characteristic
It is mandatory to set an aggregation for the those fields.
The reason is that the analytical engine performs a check for such fields. According to the check, if an aggregation(SUM ,MAX OR * is not provided then the analytical engine throws an error 'Data type * not allowed for characteristic' when publishing the view . This means that the data type is not supported for a characteristic and the field will be ignored.
To fix the issue, please setup aggregation for the fields per your requirement.
Custom CDS view, calculated columns, warning messages, publish CDS view, field XXXX ignored, data type XXXX not allowed for characteristic, aggregation , KBA , BC-SRV-APS-GKE , Generic CDS Key User Editor , Problem