Software: First and foremost: must be unix-like, must be able to communicate in both ways with an open-wrt router firmware distro and the devices on the local network (android, windows, linux, ipadOS systems). Must be very secure, like enterprise-grade or almost like that. Must be free and open-source. Must be somewhat fault-tolerant (so no Arch or gentoo or anything like that, i don't feel like recompiling the server's system daily). Must have these in base repos or easily installed in other methods: secure ssh client (like openSSH or such caliber), a software that enables me to securely control and see the gui of the server from android (Rustdesk? or such), (optionally i2p, dnscrypt, vpn clients, not needed if the router has them, just in case of emergency), ip camera management software, high-security intrusion-detection system, https server with css and js support (preferably command-line). Window manager: must support a very easy to use and lightweight tiling window manager (like i3wm) or if not, its installation and configuration needs to be possible and documented.
Hardware: affordable, x86_64 architecture, should be able to handle all of these at the same time, without freezing or overheating (i live in Hungary, so should be able to handle up to 40°C air temperature with stock fans or there should be space for more fans. liquid cooling is no-go).
I have considered these operating systems. Are any of these bad ideas? What you recommend that is not here?
AlmaLinux
Alpine Linux
Ubuntu Server
Rhino Linux (unofficial ubuntu rolling)
Debian Testing
Void Linux
FreeBSD
I run all of these or their equivalents in docker containers and have up to date versions of them. to me it makes management easy and the system clean from random files at random places. just one example: fortunately it does not need babysitting but i2p keeps its files in a very disorganized way inside the container, and I would never want to install it directly to the system (maybe unless the system would be dedicated to that)
yes, i2p on any other system than android is a massive trainwreck. I also plan to use docker containers