Mushy brakes are most of the time the result of air in the system. The issue with the front brakes is that it's sometimes hard to get all the air bubbles out of the system.
There are two tricks that I found work very well.
Pull the brake lever and zip tie it tight to grip, leave it overnight. This will hopefully help the air bubbles to the top, clearing the system. It should be back strong in the morning.
If that doesn't work, step number two is to take the front brake assembly off the bike and suspend it from the ceiling with some wires, keeping it as high as possible. The idea is to get the air bubbles to find their way to the top, back in the reservoir.
These two tricks should work most of the time and avoid messy and complicated bleeding of the system.