Can you not hit the balloon on different sides? My first thought was having the ablative mass on two paddles on either side and hit that to turn, but that adds mass that the balloon must lift.
Didn’t I just say that in what you quoted?
I thought you wrote, “Different lasers” and hit the balloon rather than paddles or, better, rudders. I was thinking of using a single laser to hit a wide rudder on different sides to turn the balloon.
That’s technically called “lithobraking”.
I thought it was known afterwards as, “Thank you, Jesus!”
If you were only interested in getting from point A to point B without having to make any turns , how about a cannon or a rail gun? You’d have to use something like parachutes or retro rockets for landing.
Low atmospheric density means that Mars parachutes must be huge - and thus heavy, expensive, and hard to re-use.
Retro rockets have the same drawbacks, with the additional one of needing sophisticated electronic control (which would have a tough time surviving the acceleration).