I've been a newbie too and tried to use FreeCAD as others mentioned but I found myself enjoying build123d (basically a python library that uses an long-existing technology called OpenCascade and a viewer called OCPViewer generally used within visual studio code).
The learning curve is still there, but I felt more empowered to adjust/share 3d printing designs made in it over dealing with quirks of GUI-based CAD applications. The discord community on there is rather helpful too.
I'll still use FreeCAD on occasion as a secondary viewer for stl files, though my hope is to use build123d entirely including for describing joints as well.
BTW there is an open source project on GitHub named 'Mayo' which is a pretty incredible viewer for 3d files including most CAD formats. 'F3d' is another great viewer. Both are cross platform.
The learning curve is still there, but I felt more empowered to adjust/share 3d printing designs made in it over dealing with quirks of GUI-based CAD applications. The discord community on there is rather helpful too.
https://build123d.readthedocs.io/
https://github.com/bernhard-42/vscode-ocp-cad-viewer
I'll still use FreeCAD on occasion as a secondary viewer for stl files, though my hope is to use build123d entirely including for describing joints as well.