The gurgling would indicate a loss of prime, which would be consistent with a difficult start.

Loss of prime would indicate a leak int the low pressure fuel system. If the leak is between the pump and the tank bulkhead, there would be no outward signs.

Repeatedly starting the engine with air in the fuel system will eventually damage your HPFP, so keep that in mind as you work through this.

Also, the lack of comms with the DDE when not running, and the light up dash would indicate a more serious electrical fault. What is the condition of your battery?

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