This video explains how to delete a connection using REST API.

Refer to the following documents for more information:
Login V2 call: https://docs.informatica.com/cloud-common-services/administrator/current-version/rest-api-reference/platform-rest-api-version-2-resources/login.html

Login V3 call: https://docs.informatica.com/cloud-common-services/administrator/current-version/rest-api-reference/platform-rest-api-version-3-resources/login.html

Connections: https://docs.informatica.com/cloud-common-services/administrator/current-version/rest-api-reference/data-integration-rest-api/connections.html