Must include AWSEBDockerrunVersion key in the Dockerrun.aws.json file - node.js

Question

Trying to move my Docker Compose application to Elastic Beanstalk and having some issues.
Been struggling with this for like a week now, come pretty far but still some big issues. I converted my docker-compose.yml to a Dockerrun.aws.json using container transform:
{
"AWSEBDockerrunVersion": 2,
"containerDefinitions": [
{
"entryPoint": [
"/client/entrypoint.sh"
],
"essential": true,
"memory": 512,
"image": "nodejs",
"links": [
"server_dans_backend:server_dans_backend"
],
"name": "client_dans_backend",
"portMappings": [
{
"containerPort": 3000,
"hostPort": 3000
}
]
},
{
"environment": [
{
"name": "POSTGRES_DB",
"value": "ABC"
},
{
"name": "POSTGRES_USER",
"value": "ABC"
},
{
"name": "POSTGRES_PASSWORD",
"value": "ABC"
},
{
"name": "POSTGRES_HOST",
"value": "ABC"
}
],
"essential": true,
"image": "postgres:14-alpine",
"memory": 512,
"name": "db_dans_backend",
"portMappings": [
{
"containerPort": 5432,
"hostPort": 5432
}
]
},
{
"essential": true,
"image": "nginx:alpine",
"memory": 512,
"links": [
"server_dans_backend",
"client_dans_backend"
],
"name": "nginx_dans_backend",
"portMappings": [
{
"containerPort": 80,
"hostPort": 80
}
]
},
{
"entryPoint": [
"/app/server/entrypoint.sh"
],
"essential": true,
"image": "alpine:python",
"memory": 512,
"links": [
"db_dans_backend:db_dans_backend"
],
"name": "server_dans_backend",
"portMappings": [
{
"containerPort": 8000,
"hostPort": 8000
}
]
}
]
}
Pretty straightforward - Node (NextJS), Python (Django), Nginx and Postgres
My problem is this, it doesn't work in prod and whenever I try eb local run I get the following error:
ERROR: ValidationError - The AWSEBDockerrunVersion key in the Dockerrun.aws.json file is not valid or is not included.
Even weirder, when I actually eb deploy I get this:
Instance deployment: 'Dockerrun.aws.json' in your source bundle specifies an unsupported version. Elastic Beanstalk only supports version 1 for non compose app and version 3 for compose app. The deployment failed.
But there is no version 3 for this file format.
I'm not particularly sure why this is a problem though since the key is clearly included. I read it could be a problem if your EB platform isn't multidocker but I believe my platform is correct.
When I run eb platform show I get the following:
64bit Amazon Linux 2 v3.4.16 running Docker
which I believe is valid - the only other option would be the ECS+EB option which I don't believe works with eb local run anyway.
Thank you in advance, been really struggling with this.