We need more landmark at the same time

In my opinion, in order to keep the game balanced, the number of landmarks that each civ should have at the same time should be similar
I usually play with AI.Beating Abbas compared to China is so easy because of the number of landmarks.For AI, they elo should be at the same level.
The first idea is
Add several unique buildings to each civilization, the buildings themselves have no function only as landmarks
But it costs less than an upgrade-age landmark
This is useful for team games.Team games between players of the same level often result in the failure of the entire team due to the failure of one player.Landmark Victory magnified the problem. Four or even two buildings get sniper,the game is end.When the enemy does this,These optional no extra features landmarks can be built into your teammates’ bases as a solution
Another idea is
Strengthen some basic buildings as small landmarks, such as building a reinforced stable for 500 wood, which can produce two types of cavalry at the same time
But limit the total number of builds