For example, I made a gasket for my mini PC awhile ago using FreeCAD. Designing it was a hell until I discovered the Sheet Metal Workbench in the plugin manager, and just like that, I got it designed & manufactured within ~4 days.
During my experience, most of my time was spent on learning how to use the Sheet Metal Workbench as well as how it interacts with other FreeCAD builtin features. FreeCAD itself is not that hard to learn.
Also, there are Piping Workbench too if you want to work on pipes, Wood Work Workbench if you want to do wood work etc, see: https://github.com/FreeCAD/FreeCAD-addons. Use the correct workbench for the right job will save you a lot of time.
built-in
Hyphens FTW!
Because... what they did in FreeCAD may surprise you. Image: https://pasteboard.co/XnHu73qUwSuD.png
https://www.goodreads.com/book/show/245787716-freecad-beginn...
and will be adding it to my next Amazon order.
There was a PDF I had a while back (can't remember the name) which has a bunch of shapes you had to design in a 3D CAD program, with some guiding measurements.
The shapes got harder to create as you progressed through the book. That was a good, fun way to sharpen my skills after I learned the basics.
I have it, it's great. There's a free one, I paid a few bucks for the full set. Guy has a Youtube channel too where he shows how he does a few of the designs. Good guy, I had some troubles with the payment getting through to him and then the download didn't work for some reason (some weird combination of issues, don't remember details), and he just send me the whole pack without even knowing if I was going to actually put in the effort to make the payment work.