The simplest is to make sure you're running the right elastomers for your weight. I'm 190cm/90kg and need the stiff versions.

My favorite upgrade on my Birdy is an Origin8 Strongbow loop handlebar. The sweep matches the factory handlebar so the fold is the same other than the front of the loop sticking out of the side. If you're not really sensitive to an extra few centimeters of folded width, it provides a variety of hand positions: a moderately aerodynamic position on the front, standard flatbar control on the sides, and palms on the corners is the most comfortable position. I've included a picture below to give an idea but it was taken just after I put the bars on and was my first attempt at wrapping and I didn't know what I was doing. I've since swapped to a thumb shifter next to the stem to free up the right grip and I have both sides wrapped like the right side here but without the extra cuts and tape.