Hi,
As i know, telegraf only for metrics from the proxmox, to have the log that you want to show in the Grafana, you just install Loki as log storage server and promtail to send the proxmox log to Loki.
Please read about Loki and Promtail to have the log observability.
If your log scattered on several folder, you can put the promtail scrape config to get the log and use different name.
Regards,
Fadjar