At this point I wouldn’t rely on PiHole DNS logs alone. You’d need to check network traffic from the device in general, it could use DoT/DoH.

And I suppose there’s the even-creeper Amazon Sidewalk: https://www.amazon.com/gp/help/customer/display.html?nodeId=...

I hate sounding like I’m wearing a foil hat but there are a lot of easy ways to get around trying to neuter smart devices now.