I’ve had no issues leaving my sensor (NodeMCU based MQTT multi-sensor with OLED display) in the bathroom, it’s been there for over a year now. The enclosure may be helping, but I think the DHT22 in general is not as bad as people think it is – I think all the bad opinions stem from the fact the DHT11 is pretty bad at accuracy and longevity, so people assume the DHT22 is just as bad. Bottom line, out of the 12 or so sensors I have around my house (some of them at ~3 years old now), none have failed at all so far.
I run my code on most of these and do a thorough calibration run (basically leave the sensor next to my HVAC thermostat for a few days and check the charts daily to build in any temp/humidity offsets). Lately, I have been converting them to ESPEasy, as its support for OLED screens has improved a lot and I’m able to easily configure the sensor (and add my offsets) via a web GUI.