stock davinci extruder is too slow to be any good at bridging
and you need a second fan, no ?
That helps, but the stock extrusion speed won't "pull" the filament along... and it'll just droop.
Faster, you need 60mm/s plus to get good bridging
can I see a picture of the whole item?
I use feeler gauges rather than paper and just get it as close as you can. Try to split the difference between the points. Remember if you lower the front, it raise the back... and vice versa. It's possible your z-carriage is warped, but you should be able to mostly compensate for it.
Second thing, that's the top of the print? Looks like it was hopping back and forth between those two points pretty quick and not allowing them to cool. You may need to look into a layer cooler or print a sacrificial cylinder at the same time that is the same overall height as the main print. Since the print head will have to move away to print the sacrificial object, it will let the main print cool a little.