SageMaker: Unable to run space with a GPU (ml.g4dn.xlarge or ml.g5.xlarge)

Hello.

Have you checked CloudTrail event history?
You might be able to figure out what's missing by checking the CloudTrail event history.
https://docs.aws.amazon.com/awscloudtrail/latest/userguide/view-cloudtrail-events-console.html

Also, there may be a problem with quotas on your SageMaker instance as mentioned in the link you shared.
Please check whether the quota for "ml.g4dn.xlarge for notebook instance usage" has been applied correctly.
https://docs.aws.amazon.com/general/latest/gr/sagemaker.html