Is it better to have just one OData dataSource?

My app's controllers mostly call one dataSource with no issues.

One of them, however uses three seperate datasources, and sometime returns 403 Forbidden errors when accessing them.

"dataSources": {
  "ZSV_SURVEY_SRV": {
    "uri": "/SAPUI5-ABAP-SFI/sap/opu/odata/sap/ZSV_SURVEY_SR/",
    "type": "OData",
    "settings": {
      "odataVersion": "2.0",
      "localUri": "localService/metadata.xml"
    }
  },
  "ZRUI_COMMON_SRV": {
    "uri": "/SAPUI5-ABAP-SFI/sap/opu/odata/sap/ZRUI_COMMON_SRV/",
    "type": "OData",
    "settings": {
      "odataVersion": "2.0",
      "localUri": "localService/ZRUI_COMMON_SRV/metadata.xml"
    }
  },
  "ZTC_SHOP_TRADING_CALENDAR_SRV": {
    "uri": "/SAPUI5-ABAP-SFI/sap/opu/odata/sap/ZTC_SHOP_TRADING_CALENDAR_SRV/",
    "type": "OData",
    "settings": {
      "odataVersion": "2.0",
      "localUri": "localService/ZTC_SHOP_TRADING_CALENDAR_SRV/metadata.xml"
    }
  }
}

Would it be better to incorporate the methods all into one dataSource (e.g. ZSV_SURVEY_SRV? Or should three separate dataSources be fine and present no problems?

If three dataSources are fine, why do I sometime get the 403 error?

Is there a performance advantage either way?