Yeah FreeCAD has a pretty rough learning curve. Especially since you need to learn parametric and its UI at the same time. I still mostly use OnShape because it’s become second nature, but last time I tried FreeCAD it was much easier since I only had to learn the UI.
Maybe give OnShape a try. Its interface is really good and will let you learn parametric CAD in one of the best conditions possible.
Yes this is normal. You have to group shapes to make them a single object.
On an unrelated note, TinketCAD is ok to make simple shapes quickly, but once you start working with complex geometry, it quickly becomes a nightmare. Parametric CAD (Onshape or FreeCAD) is infinitely superior in this regard.
Unfortunately Fusion360 has no official Linux support and is not easy to download and install, while Onshape is browser-based so OS-agnostic.