I find that the boss issue is mainly with the tip of the boss being able to move at relatively high speeds, which can kill the player early (I was generally finding that I was dashing a couple of frames late when I died to trying to ram through the boss). Honestly the bosses are probably fair as-is, but slightly shrinking the box on the tip (or adding an extremely short timer - 5f or less) would lead to fewer feel-bad moments for the player when they dash a frame or two too late.