I've been using Secure DNS under Custom DNS servers on my two devices. (So far, I've found the doh-crypto-sx to be the most stable and effective for DoH in the regional choices.) With the arrival of Pie on my Moto X4, I wondered if the default Automatic setting in in Private DNS should be instead Off and inquired with support@. I thought I'd pass on the reply: 1) Go to Settings –> Network & Internet –> Advanced –> Private DNS. 2) Select Automatic mode. 3) If you wish to select a certain provider (quad9, cloudflare, Adguard, Google, Yandex), you may specify it's hostname and hit Save. I'm thinking of moving from Automatic and configuring a Private DNS provider hostname as 1dot1dot1dot1.cloudflare-dns.com. Cheers.