The playbook can install and configure mautrix-telegram for you.
See that project's documentation to learn what it does and why it might be useful to you.
You'll need to obtain API keys from https://my.telegram.org/apps and then use the following playbook configuration:
matrix_mautrix_telegram_enabled: true
matrix_mautrix_telegram_api_id: YOUR_TELEGRAM_APP_ID
matrix_mautrix_telegram_api_hash: YOUR_TELEGRAM_API_HASH