This might be possible if you can configure your computer as a bluetooth audio sink, link a second device to it, mix the audio, and then connect your headphones to the computer. Never tried or looked into doing this though. It will need some third party software to pull off if you are using Windows, or some manual configuration if you are using Linux.
It won’t be convenient, but it can be done.
None.
X-Plane comes close to FlightGear. It has far-superior visuals. fully functional glass cockpits like the Garmin G1000, and simulated ATC, but the vast array of community-made planes available in FlightGear still kinda seals it for me, despite the jank.
FreeCAD has its pain points. Software like Creo Parametric is much more robust in a lot of ways, but I literally cannot run it on Linux (no mouse-wheel zoom in WINE, slide show in QEMU). Fundamentally, they are similar enough, and my work primarily takes place on a component level so I can live without the streamlined assembly workflow. Also, FreeCAD doesn’t cost >$2000, and can still do FEM analysis and computational fluid dynamics. Maybe I could find a crack for SolidWorks and try that out, but it takes a long ass time to learn a CAD system proficiently.
Everyone who learned on Photoshop says the GIMP interface is weird, but I learned on GIMP and can say the same for Photoshop.
Games are the only exception, but games aren’t fungible. Minecraft is not a substitute for Dwarf Fortress. CS:GO is not a substitute for Unreal Tournament.