If you want to do this, what you probably want is to pump your logs into a log drain, something like betterstack is good. They then allow you to set up discrepancy thresholds and can send you emails when something seems to be out of the ordinary. There’s probably a self hosted thing that works the same way but I’ve never found a simple setup. You can do the whole Prometheus, influxdb, grafana setup but imo it’s too much work, and then you still have to set up email smtp separate from that.