.ovh domains are like $2/year, if that helps.

Thanks, though your correction is also incorrect. Display managers, like SDDM, GDM, or LightDM, are the login screen. They’re called “display managers” for historical reasons, but they also run on top of the display server.

Display servers, not window managers. Window managers are built on top of X11 or Wayland.

Wayland is a “display server,” which basically means it manages the way GUIs show on the screen. X (most recently X11/Xorg) was the standard for over 30 years, but it was designed for computers 30 years ago. Modern concepts like scaling and high refresh rate displays need extensions to it, but it’s really complicated and hard to work with, so a lot of improvements that need to be made can’t be made. It’s also fundamentally insecure, as every window has access to both the contents and the input of any other window. Wayland is a modern replacement that focuses on security and expandability, and basically everything is working on switching to it. There are growing pains, but it’s constantly improving, and most distros use it by default now.

Be extremely careful. Plenty of people are really smart and malicious, so you need to isolate it from everything on your network. You’re giving random people remote code execution on your local network, which is like the worst case scenario for security.

Zigbee, Z-wave, and Matter all should work, but they need special radios that require extra hardware on your server (except sometimes Matter—some devices use WiFi, while others use Thread, which is based on Zigbee). SkyConnect gives you Zigbee and Thread. Homekit usually works too, but at this point it’s better to get a WiFi Matter device. Anything running ESPHome will work automatically. Athom has a lot of products that are preflashed with ESPHome, so the firmware is designed by the same people that make Home Assistant.

Behavior-based antivirus is extremely difficult, failure-prone, and almost entirely unnecessary because of how secure Linux is, so they don’t exist to my knowledge. Signature-based antivirus is basically useless because any security holes exploited by a virus are patched upstream rather than waiting for an antivirus to block it. ClamAV focuses on Windows viruses, not Linux ones, so it can be a signature-based antivirus, but not many people run an email server accessed by Windows devices or other similar services that require ClamAV, so not many people use it, and nobody made any alternatives.

If you’re worried about security, focus on hardening and updates, not antiviruses.

A .ovh domain is more like $3 a year. That’s what I’m using.

EMS doesn’t support bridges unless you pay for the highest tier, but the list you linked is good.

etke.cc does that.

This may not fit your needs, but matrix-docker-ansible-deploy is really good, and it uses Docker and Traefik by default.