I see another couple of options here.
An exhaust fan
I have seen this appliance in a lot of modern buildings. Well, even a number of blind bathrooms have a fan for removing smell. But I am referring to fans dedicated to dehumidification, which are insatlled in all rooms for this purpose (and smell too, of course).
The fan will pull air from inside the bathroom to outside the apartment. You keep the fan running for a few hours and you get a decent level of humidity. Air from the rest of the apartment will pour through the door, which is not obviously tight-sealed.
Mind that this must be designed properly as it must run within the walls. If your bathroom is on a perimetral wall, you might need construction permit, or at least a lot of work to make the hole.
The pros are that you can keep the door shut and the power usage is minimum. While this is similar to have a ventilator running, it's more discreet and you don't have to keep the door open.
A chemical dehumidifier
You can DIY using salt. In this tutorial I found quickly I think they are using common
NaCl. Sodium chloride is the same chemical entity that you use in the kitchen for your food, but, as comments suggested, you would prefer road salt as it's definitely cheaper because not approved for feeding.
At the DIY shop I found another type of product, along with the proper case, that is based on
CaCl2, which is a bit more irritating/poisonous when in contact with eyes or such.
The first bag of salt (1kg) this year was depleted in 3 days. Additional refills took longer to deplete. This one is half-way and running since 5 days, fyi
The pro is that you don't use power (electricity or gas) at all, but I am not sure how eco-friendly this is