This is my second print using TPU, after the calibration cube. The material is soft. The main strategy is to abandon all hope of retracting the elastic filament. Instead, to maintain a constant feedrate so the pressure in the hotend can stabilize, cross perimeters as little as possible, and do rapids as fast as possible.
It's cuz they aren't doing retraction. Retraction prevents the strings, but also is where feed problems show up if your printers feed can't handle what you are doing.