The filtration in heatpump dryers has changed a lot.
The standard used to be the filter, filter, double foam.
By now, mamy dryers just use 2 nylon filters behind each other.
The more filters the more airflow is impeded, but the "cleaner" the heat exchanger stays.
Miele takes that all the way on their large commercial heat pump dryers with the CleanStream design.
Why they haven't used the full pressure mains water they have to flush the condenser periodically is a good question though.
Adds a valve and a bit of electronics, but would certainly go towards longevity.