Speed in firmware (e.g. Marlin) will prevail over speed set in slicer.
For example, if speed in Marlin is limited to 100 mm/s for x axis, and you set a maximum travel speed of 130 mm/s, travel will be performed at 100 mm/s.
You should first calibrate your printer so that the speed, acceleration and other mechanical settings work well.
Then the slicer software just make use of the printer capabilities, but cannot force it to go beyond.