Thanks. I already have Log2Ram running to prolong the life of the SD. My planned disaster relief is a spare SD, already set up and taped to the box ready to swap and reboot in case of emergency. SD cards are cheap so chucking <£10 at the setup once in a while is no big thing. A fresh install on the new SD allows me to improve on what I've already done, for example the new SD I'll run DietOS instead of Raspbian, and reinforce skills. Less time efficient but that's no matter when the box is working and it's a hobby. I can then keep the old SD card taped inside the case as a physical back up. Perhaps more expensive in the long run, but an SD card taped to the inside of the case with simple instructions is an easy sell to the fiancée.
My experience with guides has shaken my confidence quite a bit. Which is fine, I'll get over myself and the point is to learn, so me hitting snags is a good thing. But, until I have a functioning back up I'm not going to be fucking with it. Facebook cannot go down on account of my education.
But if I may, I have one question, a bunch of recommendations have the setup "segregated" (I dunno the word) in Docker and Portainers but I don't understand the rationale. I wasn't intending on doing this, instead opting to install Pi-hole, Log2Ram, UFW, and the... other... softwares directly to the OS for simplicity. Why would one set up a Pi-hole et al in a containers instead of directly?
My current set up is Raspbian OS running Pi-hole as ad, tracker, malware block and DHCP (the ISP router is a Sky2 box so no IP or DNS customisation), Log2Ram and UncomplicatedFireWall.