In relation to the a23, it is a little cheaper because it costs a little wood instead of just metal and stone, but it is still expensive, in relation to cost / benefit, for example, fortress costs 900 resources.
Also has a high build time
In a23, it is a little used construction, probably due to its high value.
I had some game / forum requests to lower the cost.
Patch maintains construction time but decreases stone resource cost from 600 to 400.

Test and see if it is an improvement.