Best treatment of radon is a lot of fresh air exchange. It's what these fans do well.
When we installed the fan, the documentation mentioned failure to open 9 square feet or more of outside doors/windows could result in a window breaking from the negative pressure.
A negative pressure house is bad for more than just radon. It can cause certain appliances to vent bad stuff into the house too.
Separately, offgassing is an issue for sofas and mattresses, anything made of particle board as well, but if you put them in a low pressure environment, it doesn't drastically accelerate offgassing. If they offgas formaldehyde, they're going to keep doing it after the low pressure period has ended, so better to avoid those materials altogether.