That'll find all the problems poking holes through home routers, dynamic public IPs, etc.
Once you've got that part running, then you can look at VNC or... and hear me out... I just run the X11 apps remotely. So I'm opening their apps on my laptop, changing the config for their session and it's done.
I reconfigured Thunderbird that way when we moved email providers foe the family's email.
No need for VNC to transmit all their screen when just the app is needed 😉
Yeah, I agree... I want (and have) a NAS... and a separate Server.
The NAS is a NAS, not a TrueNas running my firewall, making coffee and keeping the house warm.
I also agree with OMV for someone starting out. I stuck with it until it got a little too containerised for my own liking and ended up building my NAS out of standard Arch because I now knew what features I wanted.
And my Proxmox is on a passively cooled small, silent, box in my home office. It will be upgraded to Incus on plain Arch one day because, again, I now know what features I want / don't want.
For OP, try things, break things, try other things... just make sure you have backups 😉
AV just uses (often multiple) vulns to do something, and with closed-source systems you can't fix it yourself, so you need an application to do it for you.
AV is a block-list approach... always needs updating, even for things you don't have. Linux can operate with allow-lists, so only the apps you have can execute.
Plus firewalls (outbound as well as inbound), SSH, secure package repos, etc.
You don't need AV, but, you can have it if you want it (maybe file-less memoey resident stuff)
So... if my SO is buying ebooks from the Kobo store, can they upload to Calibre (etc) and then someone else can download it?
They read a heap of books and want to share them with their family... who are on Kindles, with that DRM nonsense (boooo)