There is just so much that can go wrong with rocket launches if you do cursory reading about these things. A few random examples: The lowest stage cant just be "turned down" or modulated because they work by burning an inner solid rubber lining that's like an annular cylinder. The first three stages are roughly doing the job sequence: `lift off the ground -> reach target altitude -> reach target orbital velocity` and each stage is modulated for atmospheric pressure, gravity. Another limit is you can't really design it for a human in the middle(like a jet plane), so the rocket's computer needs to do everything, and when the rocket's pitch or yaw or roll(in a manner of speaking) go off beyond a nominal range its game over.

ISRO has a very good track record of launching rockets with solid state engines. I do wonder if almost all of their expertise was used for the first three stages(and they are not 3d printed)? And how much more difficult it is to make the last stage as compared to the first three, which as I understand, was the stage designed and tested by skyroot itself(manufactured by Wipro 3D).