Yeah, the bundled software for the RCX was pretty awful, and was Windows-only. That's why I used brickOS, which let me write C (or was it C++?) code to run on the RCX, and it also worked on Linux.

The next generation, "NXT", was somewhat better (I believe it's based on LabView), but I remember it being ridiculously slow and unstable on Macs.

One of my kids uses Lego's "SPIKE Prime" at their robotics club, and while I haven't used the software myself, it seems much better.