I do have photos but have decided not to post them. I was there for one night only, and overall it was just ok. If I had been there multiple nights I would have been very upset.
I understand that right now the occupancy rate maybe lower than normal due to covid, but it's not an excuse to give out dusty rooms, that were not cleaned properly. I found hair as well as visible clusters of dust. In my first room, the sheets had what looked like makeup stains.
I did ask for my room to be switched. The second room was still dusty but I had a test the next morning and was just to tired to from my long commute to deal with. I'm mentioning dust because I recently found out I'm allergic to it.
My suggestion is that you should close some of your inventory if you're not going to come in and give the room a wipe down every couple of days. Regular houses in South Korea accumulate dust very quickly, hotel rooms are no different. Also make sure to do thorough vacuuming, and if there are stains on the sheets that won't come out, please recycle the sheet.
I'll stop here, although there's more I could say.