I have Unbound and a pihole. Started with just unbound but found I needed device specific rules that I couldn’t do. So I setup pihole and some devices use that as published through the DHCP. Things like the Mrs didn’t want certain ad blocking on her devices, but I did everything else. Also means in future I can block more just on the kids devices.

Ha, DNS is the only one of those that I have sorted. I have some reading to do.

In 2025 RAID does not work. It will not protect you from errors. it’s all a mirage. The only sane option these days is ZFS.

Centralised identity management, particularly for machine logon, NFS and maybe a few of the services I run.

Just get a cheap old office PC from eBay or local market place for £50. Add your disks using ZFS (don’t use raid as it basically doesn’t work in modern systems). I’d be tempted to get one 4tb internal drive and one external usb to use as your backup drive.