Not sure if this is fixable, but the structure often spawns partially underground, this is an example

Could just redesign the structure to not have as many air blocks on the edges, so it blends in better even if clipped into the ground.
Also probably could make mossy/cracked timeworn stone to make a more unique structure if we make it out of that.

You can fill structures with structure_void, so that it can be partially buried instead of hollowing out the land, not ideal but I think the best it can be, also changed the ruin to include timeworn bricks and a campfire.

My only other idea is you can probably check the land before spawning in a structure to make sure it's flat enough, but this is honestly fine.