How do I specify or change an environment variable as part of a job matrix?

For example, here I want my job to echo "Two" and "Three" instead of "One", but github completely ignores the definition or change of the environment variable in the matrix:

name: test-test-test

on:
  push:
    branches: [ main, develop ]
  pull_request:
    branches: [ main, develop ]

env:
  MY_VAR: One

jobs:
  test:
    runs-on: ubuntu-latest
    strategy:
      matrix:
        include:
          - env:
              MY_VAR: Two
          - env:
              MY_VAR: Three
    steps:
      - run: echo "$MY_VAR2"

yields echo "One" and echo "One" in both jobs.

>Solution :

Use this context to access information about environment variables that have been set in a workflow, step, or job. Note that you cannot use the env context in the value of the id and uses keys within a step. An example is env.env_var.

GitHub provides extensive documentation about contexts at
https://docs.github.com/en/actions/learn-github-actions/contexts.