That's not an XCom limit. There's a configuration limiting the maximum number of mapped tasks: https://airflow.apache.org/docs/apache-airflow/stable/configurations-ref.html#max-map-length. The default value is 1024, you can configure this higher/lower as you prefer.

XComs are limited by their size in your database of choice: https://www.astronomer.io/docs/learn/2.x/airflow-passing-data-between-tasks#when-to-use-xcoms.