Ubuntu 22.04 LTS Server on a tiny Dell Optiplex 7000 server (Intel 12700T), strapped under my desk, hosting everything in docker:
Plex
*arrs, on top of a Gluetun container for privacy
QBittorrent, to download big files, like … eh … linux distributions
NginX Proxy Manager
PhotoPrism (I subscribe, it’s awesome, cannot recommend it enough)
Portainer, as a management interface
Wireguard VPN server, to enable me to get into my LAN and prevent having to expose anything to the public internet.
Watchtower, for keeping things up to date.
A Synology 718+ with 10 TB in a a dual SHR RAID.
PhotoPrism storage
Plex media storage
In addition, I’m hosting a couple of Wireguard VPS in the US and a Nordic country to give me access to regional content (I pay for a few regional services through friends living there - i.e. they pay monthly and I pay them yearly for an account on a region-locked service) - not sure if that counts as “self-hosting” :)