Thank for you the detailed feedback. You are right, there is inertia added to the game. I usually add just a tiny bit of inertia + reactivity to make players feel ever so slightly smoother. When there is 0 inertia, the controls can feel very stiff and rigid, like you're moving a tank.
I agree that the dashes feel kinda bad. It's due to a combination of factors other people have also pointed out.
- There is no grace time after landing
- You won't dash if you release the key too early
- And in my opinion, the dash is maybe a bit too long