The more frequent the data comes to Dynatrace, the better our baseline technology works, which is why we keep it at one minute by default. By increasing it you'd decrease our ability to detect changes in the metrics.
If you want to change it you'd have to do that you'd have to do that as a custom version of the extension. You can download the extension from the "Versions" tab on the hub:
Once downloaded, you'd have to change the "interval" section in the yaml (see the help: https://www.dynatrace.com/support/help/extend-dynatrace/extensions20/data-sources/prometheus-extensi...), and then sign it (see the help: https://www.dynatrace.com/support/help/extend-dynatrace/extensions20/sign-extension)
Once signed you can upload the certificate to the AG and UI, and the extension to the UI and you've got your own custom extension. Keep in mind that the new extension will not get any updates to the extension, so you'd have to redo the process if you want to get any changes that we release.