Is there an application for building/drawing stuff. I know blender exists, but its a little overcomplicated for what I'm thinking of.
Also where can I post such questions, regarding software? If this isn't the right place, tell me where I can post it.
FreeCAD is good, but maybe more complicated than you're looking for.
You might want to try draw.io / diagrams.net . It can be used in the browser or as a standalone application
Second draw.io - I've done lots of diagrams with VSCode and the draw.io plugin