Welcome!
If you don't need the higher flow rate, 3/4" hose is more flexible. I would not use steel reducers; brass or stainless are probably better choices.
Tractor Supply sells fuel hoses. You could stop by for a look, and see what you think. My guess is that your hose is older and transfer hoses do get stiff over time. There are some hoses that are marketed as being "flexible", but I would file it as perhaps "more flexible". Good fuel hose will always have grounding wire built in, so it will be stiffer than regular hose, and more like hydraulic hose.
Does that help?
It would be great to see a picture of your setup.
All the best,
Peter