I’d say anyone wanting to go this deep into a home monitoring setup will likely go with what works best for them instead of reading and following the entirety of this guide… I’m one of those people…
Wrote my own log parsing software to put into a database, display and alert through grafana, which is alerting through a homemade webhook that sends a notification to ntfy based on severity… And I also use uptime Kuma like mentioned, but my notifications channel is ntfy. No cloudflare for my internal services, only wireguard to connect home and use everything. And definitely no telegram.
Plenty of other stuff setup, but my security alerts and monitoring rely heavily on the syslog/grafana server which helps me monitor everything.
Raid 1 has saved my server a couple of times over from disaster. I make weekly cold backups, but I didn’t have to worry about it when my alert came in notifying me which drive went dead - just swap, rebuild, move along. So yeah I’d say it’s definitely worth it. Just don’t treat raid as a backup solution - and yes, continue to use an external cold storage backup solution as you mentioned. Fires, exploding power supplies, ransomware, etc don’t care if you’re using raid or not.