For anyone temporarily shutting off an Apache httpd, there's one step that's sometimes missed: a cron job or systemd timer for certbot. This can restart httpd and leave it running. In other words, in some common uses of Let's Encrypt, standard instructions such as "systemctl disable --now apache2" aren't sufficient to keep httpd off.
When using systemd, "systemctl mask apache2" can make sure that it's impossible for the unit to be started again (remove the mask with systemctl unmask once you've applied the patch).
If I need to make sure apache doesn't restart I often type "syntax error" on the first line of httpd.conf
I would suggest instead blocking 80 and 443 on UDP and TCP, via your firewall.