I created this test to calibrate bridges; it also applies to bridges over infill.

The idea is simple: each object has its own text, bridge flow, and bridge speed. 

You configure the parameters you want to test and change the text for that object, to then see which configuration you printed and then u can save the settings in your slicer.

1- Objects → Quality → Advanced → Bridge flow

2- Objects → Speed → Bridge

3 - Objects → Text_Shape → Edit Text → Put the parameters (Flow - Speed)

My perfect bridges print at 10mm/s and flow of 1.5. 

Try it with your filament.

The infill bridges are also very important; with this model you can also check if those flow and speed settings are correct for those bridges.

Increasing the flow above 1 generates a wider bridge line, allowing for better horizontal line-to-line transitions.

Comment with a photo of your bridge tests and if you need help don't hesitate to let me know.