Why is my environment variable not recognized after Cloud Run deploy? - google-cloud-platform

Question

My node application needs an environment variable as requirement to make a POST request. Everything works fine in my local machine by accessing the .env file content directly. I also did make sure to set ${_TM_API_KEY} in GCP so I can trigger it, as suggested by the docs, however it doesn't seem to recognize the variable after the application is deployed. What am I doing wrong? Any further suggestion would be deeply appreciated it. My cloudbuild.yaml looks like this:
steps:
- id: build
name: gcr.io/cloud-builders/docker
args:
[
"build",
"-t",
"gcr.io/${PROJECT_ID}/suweb:${SHORT_SHA}",
"--build-arg=ENV=${_TM_API_KEY}",
".",
]
env:
- "TM_API_KEY=${_TM_API_KEY}"
- id: push
name: "gcr.io/cloud-builders/docker"
args: ["push", "gcr.io/${PROJECT_ID}/suweb:${SHORT_SHA}"]
- id: deploy
name: "gcr.io/cloud-builders/gcloud"
args:
- "run"
- "deploy"
- "suweb"
- "--set-env-vars=TM_API_KEY=${_TM_API_KEY}"
- "--image"
- "gcr.io/${PROJECT_ID}/suweb:${SHORT_SHA}"
- "--region"
- "us-central1"
- "--platform"
- "managed"
- "--allow-unauthenticated"
images:
- "gcr.io/${PROJECT_ID}/suweb:${SHORT_SHA}"
More details: the code where the API_KEY is being referenced is in the following header:
const headers = {
TM_API_KEY: process.env.TM_API_KEY,
"Content-Type": "multipart/form-data",
"Access-Control-Allow-Origin": "*",
};
And my .env file looks like this:
TM_API_KEY=_TM_API_KEY
It is a bit unclear for me if I should reference the trigger variable here as well (_TM_API_KEY) or write the key value.
After that, when doing a form post request, the server responds with a CORS policy error telling that such endpoint couldn't be reached. I tried by hard coding the API_KEY in the headers and everything works fine, no errors whatsoever.