WRL or (decentralized) WRL - yes or no? Advantages and disadvantages?

Why not? Just replace it and that's it...

Every manufacturer recommends regular maintenance of ventilation systems themselves; a knave who thinks ill of that.

Every car manufacturer recommends that too, and everyone obediently goes to the workshop (or does it themselves) once a year and replaces (or has replaced) the pollen filter... but that is normal and nobody has concerns or anything... it's the same technology... just in the car, not in the house...

...The frequently praised tech guru Konrad Fischer here...

That was a joke, right?

In our rental apartment, a filter package cost 100 euros - that was really a cost driver. Officially - there were also cheaper copies available.

If you read the questions about ventilation or building services in general, the type of filters is probably the last thing the builder thinks about

By the way, I didn’t pay any attention to that either

Well, if you decide on a controlled residential ventilation system, you should definitely think about the model/pros and cons of it. Besides, (pollen) allergy sufferers will certainly consider it. And there are quite a lot of them.

I usually don't read most questions/decisions here and elsewhere - but it doesn't matter anyway.

This question, like some others, is better suited for a search engine than for a forum.

Just so...

My central controlled residential ventilation is only audible at full load... under normal operation you usually don't hear anything...