Hi
@Zesty feline, welcome to the forum.
As far as I'm aware there is no way to set/change lot sizes, but you can always bulldoze a lot if you need to. Newcrest is a town of blank lots in different sizes so good for building in. When you are building you have the option to save the whole lot or each room separately for greater flexibility.
The screenshot you posted shows a basement room which is why there is no landscape or other surroundings. You can build 2 basement levels per lot and up to 5 levels above ground, which includes the roofspace which can be made tall enough to use as rooms. I'm not aware of a mod to make the above ground levels look like basement but you can find mods to change the skyline and remove some of the surrounding landscaping. Mod the Sims is probably the best place to look, I think 'Bakiegaming' has some skyline removers on there.
Check out the building tutorial on the guide for more info & ideas:
http://www.carls-sims-4-guide.com/tutorials/building/houses.php and there are plenty of youtube tutorials as well.