Yes. Welcome to underactuated control, where you have more output goals than control parameters. That's why this is rocket science.
Here's a way to start thinking about this. Consider the 1D case, stopping a car with the goal of being at zero speed at a specified point. 2 goals, one controlled input. This is an under actuated problem. Setting a constant deceleration is not enough to do this. However, if you have a deceleration start time and a deceleration value after that point, you now have two variables, and can solve for zero speed at the desired point. This is essentially what Space-X is doing in the vertical direction.
They have limited ability to throttle the main engines (off, or 70% to 100%), and I suspect that in the final landing phase, they use that range to keep the vertical component constant while doing any horizontal positioning. The main engines gimbal; they don't have to change attitude for minor horizontal adjustments. So the simple approach is to get the attitude stabilized on approach, and the landing vertical. Their successful landings look like that. Their unsuccessful ones show non-vertical attitudes as the control system tries to make big horizontal adjustments.
