dynamically set maximum number of requests in envoy rate limit service

Question

We use Envoy rate limit service to limit the number of requests hitting our service.

Deployment is similar to this:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: envoy-rate-limiter
spec:
  replicas: 2
  selector:
    matchLabels:
      service: envoy-rate-limiter
  template:
    metadata:
      annotations:
        cluster-autoscaler.kubernetes.io/safe-to-evict: "true"
      labels:
        service: envoy-rate-limiter
    spec:
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                  - key: service
                    operator: In
                    values:
                      - router-$(ConfigMap.BRANCH)
              topologyKey: kubernetes.io/hostname
      securityContext:
        runAsUser: 1001
        fsGroup: 1001
      containers:
      - name: envoy-rate-limiter
        image: envoyproxy/ratelimit:e059638d
        imagePullPolicy: Always
        ports:
          - containerPort: 8080
            name: http
            protocol: TCP
          - containerPort: 8081
            name: grpc
            protocol: TCP
        volumeMounts:
          - name: ratelimit-config
            mountPath: /data/ratelimit/config
            readOnly: true
        env:
          - name: REDIS_TLS
            value: "false"
        command: ["/bin/ratelimit"]
      volumes:
        - name: ratelimit-config
          configMap:
            name: ratelimit-config

Configuration of rate limit service is basically this:

apiVersion: v1
kind: ConfigMap
metadata:
  name: ratelimit-config
data:
  config: |
    ---
    domain: router
    descriptors:
    - key: "METHOD"
      rate_limit:
        unit: second
        requests_per_unit: 2000
        name: overall_limit

I'd like the value of requests_per_unit to change if some other services scales up. How can I achieve it?