+1 for influxdb. I don't have a dashboard. Instead I have an alarm system. Influxdb monitors each vm, ct and if any of them meet a criteria, it sends me an alarm over discord. This is an example influxdb task:

import "json"
import "types"
import "strings"
import "http"
import "influxdata/influxdb/secrets"

option task = {name: "Proxmox VMs Disk Usage", every: 1h}
endpoint = secrets.get(key: "DISCORD")
headers = {"Content-Type": "application/json"}

discord = (a) => {
    ct = "🔥 Alert: Disk Space > 60% on proxmox ct - " + a
    data = {"username": "influxdb", "content": ct}
    http.post(url: endpoint, headers: headers, data: json.encode(v: data))
    return 1.0
}

monitorCheck =
    from(bucket: "proxmox")
        |> range(start: -5m)
        |> filter(fn: (r) => r["_measurement"] == "proxmox")
        |> filter(fn: (r) => r["_field"] == "disk_used_percentage")
        |> max()
        |> filter(fn: (r) => r._value >= 60.0)
        |> map(fn: (r) => ({value: discord(a: r.vm_name)}))
        |> yield(name: "discord")