How to download backup files which is WordPress Data on GCP?

I'd like to know how to get files from GCP about Wordpress baxkup. Background is that it has been expired free trial term of GCP. So i cannot access Wordpress on GCP...

Unfortunately, you lost your data.

Have a looks at the documentation End of the Free Trial:

• The Free Trial ends when you use all of your credit, or after 90 days, whichever happens first. At that time, the following conditions apply:

• To continue using Google Cloud, you must upgrade to a paid Cloud Billing account.

• All resources you created during the trial are stopped.

• Any data you stored in Compute Engine is lost.

• Your Cloud Billing account enters a 30-day grace period, during which you can recover resources and data you stored in any Google Cloud services during the trial period.

• You might receive a message stating that your Cloud Billing account has been canceled, which only indicates that your account has been suspended to prevent charges.