BV source problem with time step

Your .tran syntax in Qspice is incorrect and that why maxstep is not in effect.
If you compare your LTspice and Qspice .tran, you will find that different.
I answered this similar question before and you can refer to this post.
Refer to two of my reply in this link

Why are the simulation results different after updating the program? - QSPICE - Qorvo Tech Forum