I’m very sorry for your bad user experience! What you’ve described, sounds like some basic user errors which would’ve been easily solved by sticking to good modeling practices

The most egregious issue I had was in trying to loft between two faces, such that the curve between the faces was a 3D one.

In Fusion360, it's pretty damn simple, you click the first face, ctrl+ click the second, then select the loft option. Then it's pretty much done.

In FreeCad/Ondsel, in trying to look up a tutorial to see how such an operation is normally done, the only tutorial that got me remotely close was this one.

https://www.youtube.com/watch?v=fv53D00KdGQ

Following the tutorial would lead to errors, crashes, and even if it had worked, it is such a painful way to do this operation.

So this isn't simply an issue with bad modeling practices. Maybe it's a terrible tutorial and there is better options out there. But the ease in which it is possible to do this task in Fusion360 should be the gold standard.