Waryle

You can look up for:

• Setting up max authentication attemps per connection -> slows up a lot brute force attacks. If your password is strong enough, that’s already a big step to secure your server.
• Generate SSH Keys and disable password authentication -> do this only if you’re connecting through the same devices, because you won’t be able to connect from any device that has not being set up. Personally I don’t use this because I want to be able to access my server even if I’m not home and without my laptop
• Set up Crowdsec -> it’s a local service which scans logs and will block access to any suspicious IPs. It also relies on a crowdsourced list of IPs that are identified as threat and will preventively block them

ZFS Raid Expansion has been released days ago in OpenZFS 2.3.0 : https://www.cyberciti.biz/linux-news/zfs-raidz-expansion-finally-here-in-version-2-3-0/

It might help you with deciding how much storage you want