If using systemd, these look relevant:
How can I arrange to boot to console mode rather than X.
https://www.freedesktop.org/wiki/Software/systemd/TipsAndTricks/#changingthedefaultboottarget # ln -sf /usr/lib/systemd/system/multi-user.target /etc/systemd/system/default.target
With the ability to startx when I feel like it.
https://www.freedesktop.org/wiki/Software/systemd/FrequentlyAskedQuestions # systemctl isolate graphical.target
