There's a pretty simple point here that you're overlooking, and you're probably gonna feel a bit silly.
We know the Resistance flagship had fuel for one more jump, even at the very end. Absolutely, 100% confirmed.
How do we know this? Holdo jumped the ship to Hyperspace. That was the lightspeed ram everyone's been complaining about.
The simplest explanation is that they probably had the fuel to drift for 18 hours before they got below the level required for one last jump. And that the fuel to coast that long wasn't enough for a second jump; they had 1.5 jumps or something, and half a jump's fuel is enough for 18 hours of sublight, or whatever.
That the Raddus made that one last jump shows that you're wrong about something, somewhere, in that breakdown, though.