How to recover host PostgreSQL 16

This targets the systemd instance postgresql@16-main on the host (localhost:5432). Nextcloud’s primary DB in the documented compose file is the container postgres:16 — use restore Nextcloud PostgreSQL for that path.

systemctl status postgresql@16-main --no-pager
journalctl -u postgresql@16-main -n 80 --no-pager
sudo systemctl restart postgresql@16-main
ss -lntp | grep 5432

Reference: PostgreSQL.