I don’t think Loki itself parses logs on ingestion at all. I’m not sure if Promtail can ship logs to influx, I’ve only ever used it to ship to Loki. Promtail can be configured to add or parse or labels from the logs it sends, or you can just parse them at query time using builtin parsers like logfmt, json or regex. The hard part here will be figuring out the query to pull out the metrics you want to graph, which sounds like where you’re stuck already. So it’s hard to say which is actually better suited here.
You said you’re using telegraf, I assume to collect them - where are you storing/querying them? Have you looked into using Loki/Promtail for this?