Edit: - sorry, nevermind, I should have read the rest of the comments, there is a link below this comment (at time of writing)
Make sure you use the right adapter, I got an enclosure at first that wasn’t on the list, and it ended up not working. I switched to the recommended StarTech 2.5″ and everything worked.
The long-term solution for this (if you're up for it) is to PXE boot from your fileserver, so you don't need a SD card at all.
I have PiHole running myself, my original plan was to use a Pi but the last thing I wanted for that thing to die and my internet stop working. An easy enough fix, but a frustrating one.
Mine is also running on the my media server. Which... is fun. When I reboot it I have to start things VM's in a certain order or things get really unhappy.
I agree that a warning like that should be in place, I am surprised though that a new card worked for you. I have a drawer of Pi's that I never managed to salvage.
I've also got it doing DHCP so every device gets a <hostname>.<network>.uk domain, plus it handles some static records as well. Means it's not just a quick swapout, need to find and migrate the custom stuff I've done to it. Most of this should be in a git repo but unsure if all of it is.
The joys of overcomplicating home networking!
The Pi is fantastic for getting a taste of self-hosting / home automation as it's so cheap but by no means should it be relied on.
I moved our Home Assistant install to a docker container on basic PC and it's been rock solid after several SD cards were eaten by the Pi. Though I still have DNS (via PiHole) running on a Pi and that's starting to act up.
Only time I've found Pis reliable is when they either don't write much or are running a read-only disk most of the time. We've a network audio player using piCorePlayer[1] on a Pi running for years and never had an issue, it's running tiny core linux and only makes the disk r/w when you're upgrading or changing settings.
I'm tempted to move my MQTT server to a Pi using tiny core as that'd keep messaging up while I'm rebooting or doing some other task on my single server. Something like http://akeil.net/posts/mosquitto-mqtt-on-tinycore.html
[1]: https://www.picoreplayer.org/