No experience with anything this new, which will have a lot of innovative extra ways not to work, but from your description, you either have a pre-existing intermittent (probably electrical/electronic) problem, or you have an issue caused by running it low or out of fuel, perhaps compounded by it sitting idle for 5 years, which might give you tar and or rust in your fuel system

(The unstated reason for this idle period may also be very relevent)

I'd start with adding fuel, and checking/backflushing your fuel filter to see if it flows free, and if any rust comes out.

I think some systems have a Schrader valve for checking fuel pressure with a guage

My experience with fuel injection is limited to minimal involvement with a couple of Perkins diesels. I cleared air from the system by cracking the pipe union next to the injectors and running until fuel leaked out. You can also listen to the injector operation with an improvised contact stethescope but that wont tell if they are injecting fuel.or what the spray pattern is.

I believe its sometimes possible to do direct inspection of the operating injectors spray and pattern outside the cylinders but havn't done this.

You have to be careful, because subcutaneous fuel injection can kill.

Checked it?