Aqara Devices' ZigBee Keeps Dropping. Any Tips?

I have an Aqara water leak sensor in my kitchen and weather sensor in my living room. I added them to the ZigBee network while they were in their permanent locations - heard that should help them stay connected. For some reason they keep becoming "unavailable" in Homeassistant. I've readded them four times now.

I have other ZigBee devices from other brands and haven't had any issues with them dropping. My ZigBee dongle is a Sonoff. I've never connected the Aqara devices to any Aqara app, and was also wondering if these get firmware updates. Any ideas why these two Aqara devices keep dropping?