Only if there a) is a DNS request, b) it does not use DNS over HTTPs.

PiHole is not and never has been a reliable way to guarantee anything, regardless of how you configure it - just gets the low-hanging fruit. Plenty of devices hard-code their own DNS servers ("smart" TVs are a good example) and will happily ignore whatever DHCP gives them if they have a route to the internet.

This does work for unencrypted DNS and DoT over port 853, but it fails for DoT over any other port and DoH, which looks just like a website visit. You can't tell whether a website is acting as a DoH server without TLS inspection, and you can't differentiate between multiple domains on the same IP address either (unless a client is stupid enough to use SNI). Some clients do actually hardcode direct IP addresses to get around entirely missing DNS servers, notably Windows.