Hi! … I’m already a bit late to the party, it seems 
@bonnietwin is completely correct in his answers.
Zabbix has a set of default templates for different OS’es and applications, so it should be able to monitor already quite a few things in your network straight out of the box. And it has built in alerting to a bunch of services including mail, slack, telegram etc… making it quite easy to set that up. So it should be able to fit all your monitoring needs.
At first the learning curve may look steep and the configuration options are many and can be overwhelming. I suggest you start by checking out the Quickstart chapter in the documentation and/or this Zabbix Concepts youtube video. Make sure you clearly understand those concepts, but you should not yet bother too much about the server configuration file and all settings in it. The defaults should get you started just fine, and you can start fiddling with those once you are more familiar with how Zabbix works.
Make sure to check out the Zabbix blog and Zabbix YouTube channel as well as the YouTube channel of Dmitry Lambert, a Zabbix employee, for tons of useful guides, tutorials, explanations, etc…
As for deployment, on IPFire itself is, as @bonnietwin correctly pointed out, is not recommended, if even possible at all since it would require manually building all required dependencies for IPFire.
From what you wrote earlier, I understand you have installed the Zabbix appliance ISO. This is probably great for evaluating and exploring Zabbix a bit… but it is absolutely not recommended for production use.
See the requirements in the Zabbix documentation to get an idea of the minimal hw requirements.
I myself run Zabbix at home in a kvm virtual machine with 2vcpu’s and 4Gb ram assigned, running openSUSE Leap 15.5 with Apache, php, MariaDB and Zabbix, all in the same VM. Currently it processes an average of 33 incoming values per second monitoring 15 hosts (including IPFire) without breaking any sweat.
Anyway, I would recommend to install Zabbix server on a supported OS you are familiar with. Also check out this step-by-step deployment quide video.
About the breaking of your Zabbix instance… I don’t know what to say… I have been using Zabbix since 2009, set it up and maintained it in a handful of companies, and I’m still maintaining quite a big instance at my current company as well as experimenting with it at home. With several sudden and unexpected downtimes over the years due to power, failing network, storage/SAN etc… I may have been lucky, but I have never seen Zabbix break, unable to be recovered. Certainly not due to a power failure. The underlying databases I’ve used (MySQL, MariaDB, PostgreSQL/TimescaleDB) where always able to recover themselves without much manual intervention.
I do actually have never used the appliance ISO… maybe that’s one of the reasons why it is not recommended to use for production…