So... I would probably not be able to do better myself because those builds are already really really good and impressive, but since you asked for constructive feedback I'll try to point out what are the things that could make your builds even better
For your giant build, I would say you could are more details on and between the pillars. As it is big, we need more details or else it looks a little bit empty. I don't know exactly what is this build for, but you could also add a little more relief and volume on the ground. We can't really see with those screenshots but it seems kinda flat. Plus you could try adding more details like paths, and make a more "logical" terraforming by making the differents blocks percentage differents on certains parts of the map. Sorry I don't know how to properly explain that.
For your tiny builds, firt of all they are really cute. In my opinion you should try doing less diagonal builds. I'm not telling to do straight lines, but mix the two. Like, instead of doing 1 bloc, 1 bloc, you could do, idk, 3/4 block ? I think having that much 1 block diagonals kinda break the homogeneity of your build. Doing that could also alllow you to put more details without the build being overloaded.
Sorry if I'm not very clear. Again, english is not my first language and I'm kinda struggling to explain myself in particular contexts.