Look at QCad. They have a paid ($40), and a free version that is fully functional and open source. It's the most autocad-like app out there, so learning that has the advantage of learning the UI of autocad too.
LibreCad that others suggested was forked from Qcad about 15 years ago and hasn't moved much in terms of features. While QCad has. So in my opinion, it's the best solution.
Then there's Freecad, but that's more about 3D cad, and it's more complicated overall.