But on a default 13.2 installation, systemd’s on-disk journal is enabled by default. You can access it via “journalctl”.
To get back the old /var/log/messages, just install a syslog implementation. There’s rsyslog (the default in 13.1), syslog-ng, and syslogd available. Nothing more should be necessary.
In that case, you maybe might want to disable systemd’s persistent journal to not store the logs twice. Just remove the directory /var/log/journal/ for that. “journalctl” will still work, but will only show the current boot’s log.