If you know how to program, build123d is a FOSS option that isn’t FreeCAD! You can create objects directly from Python code, including fillets and chamfers! I’ve been playing around with it a lot and while there’s definitely a learning curve, it’s pretty powerful! There’s a VS Code addon that allows you to visualize what you’re working on and visually debug as well. I can do a lot of things I couldn’t do in OpenSCAD (which is another easier code cad option).