OS: NixOS (high learning curve but its been worth it). Nix (the config language) is a functional programming language, so it can be difficult to grok. Documentation is shit as its evolved while maintaining backwards compatibility. If you use the new stuff (Nix Flakes) you have to figure what's old and likely not applicable (channels or w/e).
BYOD: Just using LVM. All volumes are mirrored across several drives of different sizes. Some HDD volumes have an SSD cache layer on top (e.g., monero node). Some are just on an SSD (e.g., main system). No drive failures yet so can't speak to how complex restoring is. All managed through NixOS with https://github.com/nix-community/disko.
I run stuff on a mix of OCI containers (podman or docker, default is podman which is what I use) and native NixOS containers which use systemd-nspawn.
The OS itself I don't back up outside of mirroring. I run an immutable OS (every reboot is like a fresh install). I can redeploy from git so no need to backup. I have some persistent BTRFS volumes mounted where logs, caches, and state go. Don't backup, but I swap the volume every boot and keep the last 30 days of volumes or a min of at least 10 for debugging.
I just use rclone for backups with some bash scripts. Devices back up to home lab which backs up to cloud (encrypted with my keys) all using rclone (RoundSync for phone).
Runs Arrs, Jellyfin, Monero node, Tor entry node, wireguard VPN (to get into network from remote), I2C, Mullvad VPN (default), Proton VPN (torrents with port forwarding use this), DNS (forced over VPN using DoT), PiHole in front of that, three of my WiFi vlans route through either Mulvad, I2C, or Tor. I'll use TailsOS for anything sensitive. WiFi is just to get to I2C or Onion sites where I'm not worried about my device possibly leaking identity.
Its pretty low level. Everything is configured in NixOS. No GUIs. If its not configured in nix its wiped next reboot since the OS is immutable. All tracked in git including secrets using SOPS. Every device has its own master key setup on first install. I have a personal master key should I need to reinstall which is tracked outside of git in a password manager.
Took a solid month to get the initial setup done while learning NixOS. I had a very specific setup of LVM > LUKS encryption /w Secure Boot and Hardware Key > BTRFS. Overkill on security but I geek out on that stuff. Been stable but still tinkering with it a year later.