You can forward logs from Mailcow to external logging service. First you need to configure your containers, please refer to mailcow docs and docker doc, from there you can go multiple ways,..
You can use some kind of exporter to your MySQL database, think Logstash can perform this. But as I do push to another service (paid in cloud or preferably self-hosted) specifically build for logging and observability for example Loki/Grafana or Logstash/Elastic or Graylog or something else
These services can collect more, like CPU, RAM, IO usage, telemetry from website apps (if you have any), you can make alerting for plenty of stuff host is down, database is slow,…
Also just notice there is at least partially Grafana solution in docs now,…