Is there something comparable to Unity’s “Scriptable Objects” (https://unity3d.com/de/learn/tutorials/modules/beginner/live-training-archive/scriptable-objects) in PlayCanvas?
Unfortunately no. There are ways to get similar behaviour but requires the developer to implement themselves.
Can you give any pointer to how?
In Unity, a scriptable object is effectively a Monobehaviour without a transform and exists in the assets ‘registry’. You can do something similar in PlayCanvas by having a ‘scriptable object’ as an entity in the scene.
If you have more than one scene, then you have to do some more work on scene loading to get it to work correctly (have one core scene that has all the global objects, ‘scriptable objects’, etc and then additive load/remove other scenes when needed).