Basic software

apt install pv xz-utils p7zip-full screen acpi iperf rsync strace curl nmap whois htop sudo vim lsb-release
apt purge nano -y

Use chrony (over systemd-timesyncd)

apt install chrony
vi /etc/chrony/sources.d/vikings.sources
server ntp0.vikings.net iburst
server ntp1.vikings.net iburst
server ntp2.vikings.net iburst
server ntp3.vikings.net iburst
#pool 2.debian.pool.ntp.org iburst
vi /etc/chrony/chrony.conf 

Comment out or delete any servers

chronyc reload sources
watch chronyc sources