Is it possible to create a GUID in survey123? I know its not a good idea to use OBID as a key but I do not see a way to enable Global IDs.
In a survey, esriFieldTypeGUID is a valid field type in Survey123 Connect, so you can create one.
There is an option when publishing the survey to use GlobalID as the primary key for the attachment relationship, though I have not had any success posting a survey to the resulting feature service
I did have success writing GUID values to an esriFieldTypeString 255
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