Running Metabase behind AWS ALB with Cognito Auth

We are trying to run Metabase behind an AWS ALB that uses direct connection to Cognito to authenticate users. We are trying to run the app with a base url of /metabase (eg. our url to get to metabase should look like https://mydomain.com/metabase)

Our configuration is the following:

ALB Listener Rule:

Paths:
  /metabase
  /metabase/*
  /api/*
  /app/*
Auth:
  Cognito User Pool
Forward:
  metabase-target-group -> points to ec2 on port 4000

EC2:
Running metabase/metabase-enterprise:latest container with the following docker-compose

version: "3.3"
services:
  grafana:
    image: metabase/metabase-enterprise
    user: root
    container_name: metabase_app
    environment:
      MB_DB_TYPE: postgres
      MB_DB_DBNAME: metabase
      MB_DB_PORT: 5432
      MB_DB_USER: *redact*
      MB_DB_PASS: *redact*
      MB_DB_HOST: *redact*
    ports:
      - "4000:3000"
    networks:
      - platform_network
networks:
  platform_network:
    external:
      name: platform_network

Metabase Config:

Site Url: https://mydomain.com/metabase

The Error:

When we navigate to the our url, we are getting the following error:

We're a little lost...
The page you asked for couldn't be found.

The container logs for each request are:

2023-05-11 15:12:22,035 DEBUG middleware.log :: GET /api/user/current 401 529.2 ┬Ás (0 DB calls)
"Unauthenticated"

2023-05-11 15:12:22,101 DEBUG middleware.log :: GET /api/session/properties 200 69.1 ms (1 DB calls) App DB connections: 0/4 Jetty threads: 6/50 (1 idle, 0 queued) (45 total active threads) Queries in flight: 0 (0 queued)

An inspect on browser shows the following error logs on client side:

Warning: the Metabase site URL basename "/metabase/" does not match the actual basename "/".

Refused to apply style from 'https://mydomain.com/metabase/app/dist/styles.css?10cd540a50370a0ca610' because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.

Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'error')

Looks like its trying to redirect us to the auth endpoint but failing? Any help on this would be greatly appreciated!