Ubuntu 18.04 slow boot (apt-daily.service)

This service doesn't need to be in boot
Edit the timer for some time later

sudo systemctl edit apt-daily.timer

with this:

# apt-daily timer configuration override
[Timer]
OnBootSec=1d
OnUnitActiveSec=1d
AccuracySec=1h
RandomizedDelaySec=1d

To see if it works:

systemd-analyze blame