A separate state for launch zones could work, though it sounds a bit too complex.
What if you revert the dampening control? I.e. dampening is always enabled except when pressing A/D. Could that work?
It would break using the booster zones then, you would launch and then immediately slow down instead of maintaining momentum.
One idea I had was to add a flag that turns off momentum when you leave a booster zone which reverts when you touch the ground or pulse. I’ve been trying to find other games that cleanly solves this issue but as far as I can tell they don’t really use gravity to propel the player but use a single force impulse.