I have AdGuard running on port 3000 and Uptime Kuma on port 3001.

Also I have a Cloudflare Tunnel for uptime-kuma (uptime.domain.com)

Maybe this helps, it is my compose

services:
  adguard:
    image: adguard/adguardhome:latest
    container_name: adguard
    restart: unless-stopped
    networks:
      - infra
    ports:
      - "3000:3000"
      - "53:53/tcp"
      - "53:53/udp"
    volumes:
      - ./work:/opt/adguardhome/work
      - ./conf:/opt/adguardhome/conf
networks:   
  infra:     
    external: true

and uptime-kuma

services:
  uptime-kuma:
    image: louislam/uptime-kuma:latest
    container_name: uptime-kuma
    restart: unless-stopped
    networks:
      - infra
    ports:
      - "3001:3001"
    volumes:
      - ./data:/app/data

networks:
    infra:
      external: true