systemd-resolved very slow 5s+ under load

[vans163]

systemd 244

Ubuntu Server 20.04

I noticed that under production load, maybe a couple hundred DNS queries per second, the resolver takes 10+ seconds to resolve a domain.

UNDER LOAD
resolvectl query archlinux.org
archlinux.org: 138.201.81.199                  -- link: enp5s0f0
               2a01:4f8:172:1d86::1            -- link: enp5s0f0

-- Information acquired via protocol DNS in 10.5834s.
-- Data is authenticated: no

NO LOAD
resolvectl query archlinux.org
archlinux.org: 138.201.81.199                  -- link: enp5s0f0
               2a01:4f8:172:1d86::1            -- link: enp5s0f0

-- Information acquired via protocol DNS in 20.8ms.
-- Data is authenticated: no