This is the way I’d go if it were me. Debian minimal, add in unattended-upgrades + rkhunter + fail2ban + ufw to keep it locked down, and then set it up as a kiosk for whatever I needed (something like here: https://github.com/PhilGoud/xfce-kiosk )

I would think the jargon would be “I chose fedia.io as my Lemmy provider,” or similar for other federated platforms.