[profmonocle]

`sudo tcpdump port 53` says yes, they do use unencrypted DNS.

AFAIK Chrome has a hardcoded list of DNS servers which offer encrypted DNS. I.E. if your DHCP server tells your PC to use 8.8.8.8, 1.1.1.1, 9.9.9.9, (or the IPv6 equivalents) it will instead connect to the equivalent DNS-over-HTTPS endpoint for that DNS provider. This is a compromise to avoid breaking network-level DNS overrides such as filtering or split-horizon DNS. It's not limited to public DNS providers either, ISP DNS servers are in there. (I've seen it Chrome connect to Comcast's DNS-over-HTTPS service when Comcast's DNS was advertised via DHCP.)

Of course, this is pretty limited. Chrome obviously can't hardcode ever DNS server, and tons of networks use private IPs for DNS even though they don't do any sort of filtering / split-horizon at all. (My Eero router has a local DNS cache, so even if my ISP's DNS servers were in Google's hardcoded list, it wouldn't use DNS-over-HTTPS, because all Chrome can see is that my DNS server is 192.168.4.1)