All that you say is true for the majority of Sonic customers that are directly connected to the Sonic network. Like I wish I was. But, alas, I no longer live in California and so ... no luck. I am lucky enough to live in Loveland, CO and we have a local community broadband provider so I have my gigabit fiber. But they are a stripped down operation. They provide a pipe to the internet and that's it. A modem, IP address and good luck.
So I *have* to use a public DNS server. Since I use Sonic for email (I know - my email is encrypted on its way to you) and other things, I would *like* to use Sonic's DNS servers.
But I'm also developing a sense of paranoia, especially as DNS queries are all that leaves my private network unencrypted.
Cloudflare is fastest, although speed doesn't matter much since I'm using pihole and it caches. Right now I'm doing DNS-over-https to Cloudflare since it doesn't seem too reasonable to give google more data than they already get from me.
Anyway, we customers who are not directly connected to Sonic are no doubt in a minority and I get it if supporting DNS over HTTPS for us, or for locally connected people who are traveling is too much effort.