They’re using Zigbee2MQTT, but you can achieve the same result in ZHA by going to the device page (for the closest device to your sensors) and clicking 3 dots > add devices via this device:
I suspect the issues you have with Aqara devices is because you’re trying to pair everything with the coordinator when there are more suitable devices nearby. Personally I never had issues with any products from this brand once I learnt to set them up the way zigbee expects.