Key history items not much discussed:

How to select which enemy targets to bomb?

20/20 Hindsight answer: Let the enemy tell you what is crucial - so bomb what has the most fighters and Flak guns surrounding it.
Bombing ball bearing factories did not work.
Bombing where railroad cross one another did not work.
German plants that turned coal into 3 products: engine liquid fuel, synthetic rubber, and explosives - should have been “top priority targets.”

Bomb during daylight or at night?

20/20 Hindsight answer: At night carpet bomb
using Mosquito aircraft or similar to mark target area boundaries with fire bombs first.

What could have Joe Stalin done to shorten the war and save huge numbers of Soviet soldier deaths.

20/20 Hindsight answer: If Stalin had supplied fuel and allowed Britain and the USA to set up airfields in Russia
so the bombers could bomb going West-East, then landing, refuel, reload bombs, rest crew
- then bomb flying East-West returning to England,
targets would have been destroyed faster.

B-17 crews suffered especially
and the war’s end was prolonged by as much as 2 years
by above mistakes.