One question, answered from the books
When should a jungler give Dragon?
Give Dragon the moment you know no lane has priority, and give it before the fight starts, not after you lose it. A conceded Dragon costs one objective; a contested Dragon without priority usually costs the Dragon, two or three deaths, and the next play as well. Concede it cleanly and take a real trade on the opposite side of the map: camps, a tower dive window, or Herald alongside the timing. Number two matters more anyway.
The decision, as a picture
What it looks like in a real game
Bot just lost the 2v2 and their whole team is rotating down river. The greedy line is sitting in a bush near the pit and waiting for a miracle. The disciplined line is already gone: their jungler is burning 40 seconds walking to a Dragon you never intended to fight for, and you're two camps and a plate richer on the other side of the map. You didn't lose a Dragon. You sold it.
The concept: Kill discipline and the priority rule
Start Disciplined builds objective play on one check: priority first, objective second. The book's pricing is blunt, an ordinary kill does not pay for a Dragon, which is exactly why you don't donate three deaths trying to save one.
"The goal is not to always solo the Dragon; it is to always have priority on it."
"If all three lanes are in bad shape, skip the first Dragon entirely."