Please add information to the Zabbix proxy sever installation and Zabbix server installation For all linux variants along the lines of, If your corporate policy allows it,  it is highly recommended that for zabbix proxy servers and any zabbix servers running a local database that you either disable Unattended updating, or if policy does not allow it modify the autoupdating in such a way  nodes in a cluster do automatically update around the same time as if you don't you will run into a situation where the database updates when no packages that require an OS reboot install and the zabbix-proxy or zabbix-server process will be stopped and the database restarted but the proxy or server process will not be started back up again, and all zabbix nodes could go offline simultaneously.  

if you wanted to be really nice with the documentation you could include methods to disable it. 
For Debian linux family tree derivatives especially ubuntu that has autoupdate enabled by default you could either have the modify the /etc/apt/apt.conf.d/20auto-upgrades file to have lines of  'APT::Periodic::Update-Package-Lists "0";' and 'APT::Periodic::Unattended-Upgrade "0";' or to disable the  unattended-upgrades.service. 

for Red Hat Linux family tree derivative you could mention 
(RHEL 8/9/10 derivatives)   If dnf-automatic is installed on the box possibly disabling dnf-automatic-install.timer  and possibly the dnf-automatic-download.timer  and dnf-automatic-notifyonly.timer. 

(RHEL 7 derivatives) possibly disabling the yum-cron cron service if it exists. 

Rational:
We ran into a problem where the majority of our zabbix proxy servers had mysql updated over the course of an hour time frame and thus had their zabbix-proxy.service stopped, and it happened to all of the zabbix proxies in our one zabbix proxy group which stopped us from monitoring more an entire data center and the extra non data center stuff that was monitored by that proxy group. This caused us to open a case with zabbix support that could have been avoided had we been suggested to disable this on install.