CloudFormation import CDK resource, Catch-22

I am in the process of updating a CDK app to include several tags.

There is a Networking stack that has somehow gotten out of alignment with the deployed resources. It looks like some external process destroyed and re-created the Public subnet, so the ARN of the existing subnet did not match the ARN in the Cloudformation (CF) stack. In an attempt to bring the CloudFormation stack and the existing resources back into alignment I removed the non-existent subnet from the CF template. I am now trying to import the existing subnet into the stack following the instructions here: https://aws.amazon.com/blogs/devops/how-to-import-existing-resources-into-aws-cdk-stacks/

One solution to using existing resources in a CDK app is to use a resource lookup in the code. This isn't an option here because the app has been used to do the networking setup for many accounts, so I can't change it to be a lookup without impacting the other accounts.

The instructions state that a new template must be created that includes all existing stack resources in addition to the resource that is being imported, and that template is used to update the stack to include the new resource.

The stack was deployed using the CDK, which puts a "CDKMetadata" section into the Template.

If I include that "CDKMetadata" section in the updated "Import" template then it triggers this error: "Invalid template property or properties [CDKMetadata]"

If I remove that section, then it triggers this error: "You have modified resources [CDKMetadata] in your template that are not being imported. Update, create or delete operations cannot be executed during import operations."

It seems like this will make it impossible to import any resources, unless I separately delete the CDKMetadata section. Is that the intended workflow? Am I missing some other solution?