More important is properly maintained. People tend to forget to change filters. Those are a prime breeding ground for mold, and your central ventilation distributes the spores throughout the house.
That's why people should change the filter and have a yearly inspection, just like for cars.
But the filter is on the ingoing side and not on the outgoing side, so no moisture from the inside can aggregate there. Only the humidity from the outside but we've never had problems with that.
My HRV has filters for both inbound and outbound airflow. I do change my filters regularly, but even in the rainy Pacific NW I haven never seen any mold growth on either filter, and I have an RPi logging air quality data with a decent sensor, so I can see my PM2.5 and PM 10 are both near-zero.
Because we stood in front of the same decisions this year, I can only recommend to use wood not stone as building material. And wood fiber insulation. Building techniques in that area are pretty advanced. (At least I hope so, let's talk about it in twenty years again :D )
I think this has already been addressed by the sibling comment to my question. Insulation does not have to impermeable. Its purpose to prevent the loss of air carrying heat with it, not the transfer of moisture/humidity.