Don't get me wrong NextCloud is great and has a lot of helpful features out of the box, but I moved from this to just use;

• Samba: for mounting drives shares.
• CalDav: for shared calendars.
• CardDav: for shared contacts.
• Memos: for note taking, great little room that allows Markdown note with tagging for easy search and filter.
• Espo CRM: for logging communication with businesses, like utilities providers (comes in handy to refer to during disputes)

I'm also looking at installing a self-hosted office suite for word and Excel documents but haven't set this up yet.

ZoneMinder is great for home security cameras, you should be able to add your caneras using RTSP depending on the camera and whether RTSP streams are available

Couldn't you just get a regular domain and use a firewall to prevent access, so only your IP address(s) are able to access it.

I'm currently doing this myself, however I have a VPN on my local network that allows me access to my self-hosted service remotely as if I was at home.

There are other things you can do with cloudflare that will lock the sites down with authentication, but VPN and firewall have worked pretty well for my use cases.