Automatic ballista control.

Exactly, but the hero might not have the skill to control a ballista. Depending on this, the program needs to be made to work differently.

If the hero has the skill to control a ballista, then, in my opinion, in the battle settings menu, you can enable automatic control, so there will be no need to configure the program for two options (for a hero with the control skill and for a hero without the control skill). I haven't checked this (just thinking out loud) - check it yourself.

Now I'm uploading a map on which the program will be tested,
and for which a description will be provided.

If it works as I wrote above, then reflect this in the program description (the program's functionality will be improved without additional changes and settings to the program itself :)

This program will only work under the condition
that the morale of the attacking and defending armies is neutral.

Uh-huh :) Noted.

The following options are possible here:
1) apply the "Spirit of Oppression" morale debuff;

I agree with this.

2) take armies from another Castle to lower the morale to neutral.

But this needs to be checked. There is no guarantee that the enemy monster squad will not rush to the additional unit, and then not attack the ballista itself. And one more clarification. If the monster squad is divided into 7 squads :) Then, as you understand, it will most likely be a disaster. Without the program, you might still be able to try. But with the program, it's over. I remember in Best of Best, I defeated a lot of dendroids (somewhere around 250-300) with 25-30 vampires (without a ballista). The only thing that saved me was "General Slowdown". Moreover, there was such a bug. Single slowdown, in my opinion, does not work on dendroids, but general slowdown does :) Somehow, I had enough mana :)