Correction: There is a way to do it without the customObjectId, found here! Phew!
https://api.hubapi.com/crm/v3/schemas/{objectType}?archived=true
Apparently the purge endpoint is deprecated.
Correction: There is a way to do it without the customObjectId, found here! Phew!
https://api.hubapi.com/crm/v3/schemas/{objectType}?archived=true
Apparently the purge endpoint is deprecated.