My environment is pretty moist. I combated the moisture by making a box out of plywood. Printed 8 corner brackets, cut and planed the plywood into 6 segments, varnished each side then bolted it all together leaving the lid off and sealed all the gaps with silicone. I siliconed all around the top of the walls where the lid connects and let it dry. Inside I stuck an m6 x 25mm (I think) bolt through one side with a nut on the end to keep it still, the filament reel catches in place on this then I just push a much longer m6 bolt through the other side which holds it still. inside the box I have 2 silica gel packs on the floor, one stuck in each end with thumbtacks , then on the lid there’s a hole drilled for filament to feed through with two more silica gel packs thumb tacked right next to it. Feed the plastic through then bolt the lid on, it pushes down into the silicone making a decent seal and I’ve not had a single problem since. Once I’ve finished printing I remove the filament from the extruder and push it back into the box leaving just 3mm or so to grab and pull it back out next time.
There are better ways of making a box but I had all that stuff lying around doing nothing anyway so it cost nothing and was really quick and easy to build.