Starting fluid is a terrible thing to use on a diesel with prechambers, you can do catastrophic damage.

Crack the lines loose at the injectors and crank it over a few times.

Oops, see you already tried that.

So, hopefully its stiff cold oil and a slow turning engine, and maybe it saved your butt from blowing it up with ether?

I had a 300D that once cranked up at zero F dead cold, not plugged in overnight or preheated, but I never tried it again. It made so many awful noises in protest it was simply sad. That is the absolute coldest I ever tried starting a cold diesel, and after that attempt I have always plugged them in if its below 30F.

But that was with straight #1 diesel with some kerosene and gasoline added (there had previously been some extreme cold with -20F and colder). #2 diesel, or winter blend it wouldnt have worked. Straight #2 is good down to 35F or so, blended maybe will fire down to 20F or so. They might crank up at colder temps, but its a real risk of failure if its much colder.

Pull starting it might just be the trick to getting it going. Even a low compression diesel can get going that way sometimes.