I also started out with Portainer and Docker, as a beginner I thought it was easy.

I’ve not switched to a different web interface, but removed it and started using rootless podman quadlets. I do have to do some stuff myself because of this.

Not so far, I think the recommended filesystem is ext4, or if you have multiple drives, ext4 on LVM.

I’ve been using FreedomBox for years, overal I still like it. I don’t think Yunohost and CasaOS were around when I started, the alternatives were DIY from just a normal Linux distro, or NAS focused thing like OMV and trueNAS, both worse for what I wanted.

It doesn’t have a lot of apps but still some you may want. Some configuration stuff is really nice, like it makes it beginner friendly to set up Pagekite, LetsEncrypt, a firewall, ssh keys, users and reverse proxy automatically configured for the apps it does have.

Have configured some stuff outside of plinth anyway. Docker containers for apps it doesn’t have, configure apache to reverse proxy those too. I set up my storage in btrfs volumes from command line, but I think you could do it from the web interface too.

If I were to start over, I’d probably try Yunohost too, my third option would be plain Debian and diy everything rather than Casa. But for now I have no reason to try anything else.

Raid5 of three disks and keep the fourth as cold spare. That’s 16TB instead of 24, but you’re barely using your current 8, so a spare makes more sense.