OpenSCAD is a great program, but it's not like blender or fusion 360. the input is a text file, and you need to describe the object you want to model as geometrical shapes in text. It also only renders when you tell it to, not constantly.

But if you are willing to dive into it, you can get great results. There are libraries available for threads and gears and curbed shapes and such.

It does take some getting used to, even more so if you have never done any programing, but it's FOSS and can create the same output as the graphical-menu counterparts.

Edit: I had originally posted a link to some stl files I made, but my read name is on there so I removed it.