Answer
No — since Apps9 onward, setting a default value specifically for a DATE-type custom field isn't supported or allowed at all. This restriction was deliberately introduced by IFS due to specific framework-level issues that could arise from allowing default values on date-type custom fields, so there's no workaround through the custom field's own configuration. If a default date value is genuinely needed, it would have to be populated some other way, such as via a Custom Event, rather than through the custom field's own Default Value setting.