OTEL metrics' resources attributes gets dropped when exported to Grafana cloud

I faced the same issue recently, but in my case I used grafana-alloy (previously agent) and found out how to solve it there:

otelcol.exporter.prometheus "to_prometheus" {
  forward_to = [prometheus.remote_write.default.receiver]
  resource_to_telemetry_conversion = true
}

the resource_to_telemetry_conversion is the key