I have a suggestion:
Merge the original two research nodes into one, split them as shown in the image, and place them in the research tree immediately after the second node listed in the research prerequisites.
I hope I haven't overdone it with the number of material types required for construction—hopefully, the game engine can handle it. The items listed after the plus sign are only obtainable via ocean exploration at the time of research, which is why the quantities are relatively small. I’ve added two additional materials to ensure that these structures aren't too easily accessible for mass construction. As for the names of the new research nodes, I chose them to stroke your modder ego a little bit.
Reason for the proposal:
By the time a player gets to them, they no longer have much of an impact on gameplay, in my opinion. Especially the small warehouses.

Would you be willing to implement this proposal? If so, it can be done after update 4.3.