CloudFlare provides a performant recursive nameserver along with a promise to never surveil their users.
Their Linux quickstart involves modifying the standard C library's resolver (i.e. /etc/resolv.conf) which is a terrible idea if you are using most of the popular flavors of Linux as a daily driver desktop OS because they're likely using dnsmasq or resolvconf or both to declare the contents of that file.
For what it's worth, here's shellcode to quickly reconfigure an existing Network Manager saved connection with nmcli.
# make a note of the name of the connection you wish to configure e.g. "WiFi Secure"
nmcli connection show
# save the name of the connection in a variable
export CONN="WiFi Secure"
# paste the following in your terminal to reconfigure DNS
nmcli connection modify "$CONN" \
ipv4.ignore-auto-dns yes \
ipv4.never-default no \
ipv4.dns "1.1.1.1"
# reactivate the saved connection
nmcli connection up "$CONN"
# optionally restore default DNS (DHCP)
nmcli connection modify "$CONN" \
ipv4.ignore-auto-dns no