Tower of fidelity has some issues:

1. You cannot perform an easy upgrade from lookout towers, you must manually destroy the lookout tower first and then manually build the tower of fidelity in its spot. This is further complicated by the fact that the way manual destruction works you cannot tell which tower is which when you have multiple.

2. If you destroy a lookout tower and then build a tower of fidelity in its place, then it will still list regular lookout towers as available for construction in the city. But just lacking in any space to construct them. (and vice versa if you have regular lookout towers and no tower of fidelity, but that isn't an issue since the tower of fidelity is an upgrade)

3. Unlocking the tower of fidelity removes the tower of truth from your build list. when it should be an incremental step.

4. Presumably the tower of truth has the same issues as above.

My suggestion is that those 3 towers act as incremental upgrades.

A. Make unlocking tower of fidelity require first unlocking tower of truth.

B. Make tower of truth an upgrade to basic tower, and tower of fidelity an upgrade to tower of truth. Such that they have to be built in order, and reduce their prices to account for this