Rattly gearboxes not under load are very common, just most cars mask them with weight, or the problem isn't evident because of what I would say are ultimately badly made gearboxes, in that their input shafts, flywheels, and maybe clutches, have too much springing or inertia/weight.
The sportier the setup, the more noisy things get basically.
I'm sure you can engineer the noise out somewhat with very fine tolerances and some super fancy gearbox lubrication system, but why bother for noise at idle on a 'normal' car?
Interesting to note. Get any car that is almost silent in this regard, and fit a lightweight paddle clutch, and listen to it afterwards. It is just the nature of the input shaft rattling around more due to less at idle inertial mass and/or less inertial mass springing (flywheel/clutch plate combo)
Almost 100% sure it is normal. If it develops then it's an issue, if it's just staying the same I'd not worry, and it sounds like ALOT of people have it and it's staying the same, ergo, it's normal
Dave