How to change the dag bag folder for Airflow web ui?

It looks to me like you have multiple Airflow installations. I think you have to check the UI in the Admin -> Configuration menu.

That will tell you which Airflow is active and set as AIRFLOW_HOME and AIRFLOW_CONFIG.

If the AIRFLOW_CONFIG environment variable is not set, it will always default to your home directory. You'll have to set it to something like this: AIRFLOW_CONFIG=$AIRFLOW_HOME/airflow.cfg.