I've linked Proxmox with Influxdb2 via the Metrics Server configuration. I can see data on Influxdb, and on Grafana, but I cannot figure out how to add lm-sensor and other additional data to be passed from Proxmox to Influxdb2 via the API.
there is nothing in pve built-in for that, you would have to manually send the lm-sensors data to the influxdb instance
there is e.g. telegraf (from the same people that make influxdb) which is basically a montoring daemon for influxdb, which should have a sensors plugin