I know this is not what you want, but actually:
$ apropos dns
[...]
resolvectl (1) - Resolve domain names, IPV4 and IPv6 addresses, DNS resource records, and services; introspect and reconfigure the DNS resolver
[...]
$ man resolvectl
[...]
dns [LINK [SERVER...]], domain [LINK [DOMAIN...]], default-route [LINK [BOOL...]], llmnr [LINK [MODE]], mdns [LINK [MODE]], dnssec [LINK [MODE]], dnsovertls [LINK [MODE]], nta [LINK [DOMAIN...]]
Get/set per-interface DNS configuration. These commands may be used
to configure various DNS settings for network interfaces. These
commands may be used to inform systemd-resolved or systemd-networkd
about per-interface DNS configuration determined through external
means. The dns command expects IPv4 or IPv6 address specifications
of DNS servers to use. Each address can optionally take a port
number separated with ":", a network interface name or index
separated with "%", and a Server Name Indication (SNI) separated
with "#". When IPv6 address is specified with a port number, then
the address must be in the square brackets. That is, the acceptable
full formats are "111.222.333.444:9953%ifname#example.com" for IPv4
and "[1111:2222::3333]:9953%ifname#example.com" for IPv6. The
domain command expects valid DNS domains, possibly prefixed with
"~", and configures a per-interface search or route-only domain.
The default-route command expects a boolean parameter, and
configures whether the link may be used as default route for DNS
lookups, i.e. if it is suitable for lookups on domains no other
link explicitly is configured for. The llmnr, mdns, dnssec and
dnsovertls commands may be used to configure the per-interface
LLMNR, MulticastDNS, DNSSEC and DNSOverTLS settings. Finally, nta
command may be used to configure additional per-interface DNSSEC
NTA domains.
Commands dns, domain and nta can take a single empty string
argument to clear their respective value lists.
For details about these settings, their possible values and their
effect, see the corresponding settings in systemd.network(5).
[...]
Not too bad in my opinion. (I didn't actually knew before how to set the DNS server, never needed to do it.)
