I have the exact same issue with my machine (identical model). Family member took the MacBook in for third party repair due to the question mark issue during startup (steady, not blinking). This third party shop wasn’t able to fix the issue and ended up keeping (stealing) the original SSD after they gave the MacBook back. After disassembly and inspection, I found no issues besides the missing SSD. Ordered a new compatible SSD from OWC and installed using precautionary measures (anti-static mat and careful lifting/plugging of stick into SSD connector). Machine hadn’t previously run High Sierra and didn’t have updated firmware/EFI to support the SSD. Resolved that issue, installed High Sierra to SSD, and machine was working for a week before stability problems occurred. Further inspection and use of Apple Hardware Diagnostics (AHT?) during boot reveal the VDH002 error which indicates a storage drive issue — from further research, this error could be caused by the SSD chip itself (unlikely in my case), a broken/malfunctioning SSD connector/port on the Logic Board (maybe…), or a corruption within the firmware/EFI chip (possible).
There is another thread discussing the connector and EFI corruption issues here:
Random freezes & VDH002 "There may be an issue with a storage device"
**See answer by https://www.ifixit.com/User/1850118/carl...
posted September 13 for a MacBook Pro with similar issues…**
I have no definitive answer for this problem due to the factors that could cause the issue you’re having, but hopefully this provided some extra information to consider.