Have you seen the tutorials for FreeCAD by MangoJelly?https://m.youtube.com/channel/UCUWhaOxsRk_5oPPq00_Y7Dw
FreeCAD is the most complete open source CAD project you’ll find. I agree it is a steep learning curve, but it pays off to work through it, if you want to 3D print your designs.
If you want to create 3D models for games, or what not Blender is, as you say a great option.
You’ve got Linux Show Player (https://github.com/FrancescoCeruti/linux-show-player?tab=readme-ov-file) that will do audio cues in a familiar way, if you’re used to Qlab.
I’ve got Resolume Arena working through WINE. It does require some tweaking to get it to start, and the preview monitors are a little glitchy, but fullscreen output and ArtNet input works just fine.