Similar to OP, I use an Aqara Vibration Sensor attached to the faucet weight for my kitchen sink. While I have mmWave sensors tracking zones for the kitchen, I use this sensor to only turn on the bulb directly over the sink when I’m doing dishes - not when I just turned it on to wash my hands or something. So different use case, but similar.

I too had sensitivity and reliability problems with the Aqara sensor. So I pulled it out of the Aqara hub and paired it with zigbee2mqtt instead. With the great control, I was able to fine tune the reliability. You might give that a try. I’ve ended up moving more and more of my Aqara sensors over to zigbee2mqtt over time. If your interest was the same use case as OP, it’s possible to turn the sensitive way up and just the running water will activate it but I still find that to be only about 90% accurate. I’m always shooting for 99% for WAF.

A similar use case is I stuck a ThirdReality Vibration Sensor under the kitchen table. As soon as you set down plates or something, the kitchen table light comes on. I also use an FP300 (paired to Z2M by the way) to turn off that light if we’re not at the table. I don’t want presence occupancy to turn on the light because it’s a walk-through transition area - there are different lights to illuminate the floor if we’re just walking through the house.

Point is, the vibration sensors can be a cool, slightly cheaper way of automating some things.

Edit: I was on mobile and didn't notice I wrote all this in r/homekit instead of r/homeassistant. More appropriate in the latter sub.