Ivation 6,500 BTU Camper Air Conditioner | Portable Over-the-Window Sill AC, Fan & Dehumidifier for RV, Caravan & Motorhome | Digital Display, Temperature Control, Timer, Sleep Mode, Whisper Quiet

Your issue will always be with the compressor which is loud by definition, due to it having to physically compress the cooling gas. Only option is to move the condenser outside or only run the aircon when not in the room. Since you are renting traditional split systems won't work, so you need some form of portable one. There are ones designed for caravans that could help if you have good windows for sound insulation. https://www.amazon.com/Ivation-Conditioner-Dehumidifier-Motorhome-Temperature/dp/B0F8C39MCF

I’ve been looking at this Mr cool unit as well. Anyone have an opinion on this unit and running through th wall? https://a.co/d/0bqyFJr3