Maybe this Sonoff TH with add-on AM2301 temp/humidity sensor would be another alternative to consider. Doesn’t use batteries, very inexpensive, but it does require you to flash the firmware for a simple custom add-on for gaining an On-Off control plus monitoring of temperature and humidity. It specifies +/- 3% accuracy for humidity sensor. You can get them on Amazon but I put the link to a manufacturer website for the full specs all on one page.