If you have enough resources to train other more powerful military commanders, and SP Cao Zhen is not a core member of your team, you can consider dismantling it to get more resources to upgrade other military commanders.
However, if you think SP Cao Zhen is helpful to your team, or you lack other more powerful generals, it is also a good choice to keep him and train him.
Generally speaking, the treatment of SP Cao Zhen needs to be decided according to its own actual situation. If you have enough resources to train him and think he can help your team, it is feasible to keep him. But if you need more resources to upgrade other more powerful military commanders, then dismantling him is also a good choice.