Based on the statement:

I am trying to work on a task which will find all recent changes to any fields for an Opportunity within the system.

If having change data capture running almost continually to detect the changes you could also consider the more basic getUpdated() method that the SOAP API exposes.

You can make a single API call and find all the Opportunity records that were modified in a given time period.

Based on the statement:

I am trying to work on a task which will find all recent changes to any fields for an Opportunity within the system.

If having change data capture running almost continually to detect the changes is overkill for the requirement you could also consider the more basic getUpdated() method that the SOAP API exposes.

You can make a single API call and find all the Opportunity records that were modified in a given time period.