Home Assistant is supposed to be secure but, is it really?

I am just starting to setup a Home Assistant Server OS (HAOS) on a Rpi4. After having read and informed myself about the security and confidentiality of HAOS, everything seemed to be fine and secure.

After 24 hours of the server running, I have noticed judge picks of DNS requests, that my PiHole is not blocking. That is something like a thousand+ on every hour, while my HAOS is nearly empty yet…

Is it normal? I’m worried due to the amount of requests, for which I find no justification.
Thanx in advance for the info and advice.