Is there a way for us to disable & enable the Lambda trigger programmatically (e.g. for scheduled maintains purposes)?

You can disable and enable Lambda triggers by using following approaches with Update Event Source Mapping, based on how you are going to do it.
--enabled | --no-enabled parameters.Using AWS SDK (E.g NodeJS): You can use AWS SDK updateEventSourceMapping method with Enabled: true || false attribute.
Using AWS REST API: You can use AWS REST API UpdateEventSourceMapping with "Enabled": boolean attributes.
Note: You need to grant relevant permission for each of the approach to execute using IAM Roles/Users or temporarily access credentials.
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