We had a good one like that in our previous apartment. They consist of a large cylindrical metal "heat sink" where cold air coming in goes through the bottom half, warm air going out leaves through the top half, and the entire thing rotates at ~ 5 RPM. Not any more noisy than regular kitchen ventilation. But they need to be big, ours was the size of a small dishwasher and that was adequate for a 75 square meter apartment.

Edit: if you are buying such a thing you should get someting oversized, e.g. for a 180 square meter home you should find a unit that is specified for "200 to 350 square meters", not "75 to 200".

Yes, but they may not be effective enough; there was a big stink in the area I live where they had houses with a system like that, but the system either didn't have enough capacity, or it had to be cranked up to a point where the noise would be intolerable to the people living there.

I have a one-way system, an air pump that sucks air in through vents and out through the ceiling in a few points; I have it set to the lowest at all times because it produces a constant noise otherwise. We usually have our bedroom windows open and the back door open a crack, it should be fine even if it's not the most energy efficient.

Call me selfish, but I'd like my country to crank up electricity production, reduce its usage by datacenter and industry, and use it to heat or cool houses instead.

Opening a window is free, and not everyone has the freedom to modify their living arrangements(rented houses etc)

Yes, these are energy recovery ventilator (ERV) units. They exchange air while keeping both heat and humidity in. They are absolutely critical to health in tight house construction.