I’ve personally used Graylog[1] with success in the past. However, I’ve had an excellent time with Grafana and have been following their Loki[2] project. My company uses other solutions, so I haven’t needed it, but the Grafana stack might suit your use case.

[1] https://www.graylog.org/products/open-source [2] https://grafana.com/docs/loki/latest/