Hi Ladislav,
It’s great to see that you are challenging yourself. Unfortunately, the code is not formatted, so it is a bit difficult to read. I just focussed on your last code and formatted it for you. 
I understood your goal was to find ParticleSystem components on specific game objects via code. If I understood that correctly, your solution is how one would do that. Since components do not have any name, there is no other way to find something that does have a name, then look for the ParticleSystem.
If the DustTrail methods get executed multiple times during runtime, I would recommend to cache the reference to the ParticleSystems you found because the Find* methods in Unity are very slow and resource-intensive.
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See also:
- Forum User Guides : How to apply code formatting within your post
- Forum User Guides : How to mark a topic as solved