It's great!!! -))
When using this tactic, the Tower is probably the best choice. Position the Golems so that the enemy cannot exit through the gates; this will create a solid defense. Their health and armor allow them to do this effectively... Moreover, Golems have magic resistance and do not restore health to vampires.
And strong archers can quickly eliminate the liches...
If any creature (even a single peasant) stands in front of the gates, they will not open. Even if the creature is killed, its corpse will prevent them from opening...
And Galtran is indeed strong; you are wrong to underestimate him. Everyone knows that skeletons are the strength of necromancers