how to show Instance status for users inside the SageMaker Studio domain?

I made a script for myself in python to output running instances, maybe it is helpful for your usecase.

import boto3
import csv

client = boto3.client('sagemaker')


response_apps = client.list_apps(
    #NextToken='string',
    MaxResults=10,
    SortOrder='Ascending',
    SortBy='CreationTime',
)

running_instances = []
while True:
    for app in response_apps["Apps"]:
        if app["AppType"] != "JupyterServer" and app["Status"] != "Deleted":
            response = client.describe_app(
                DomainId=app["DomainId"],
                UserProfileName=app["UserProfileName"],
                AppType=app["AppType"],
                AppName=app["AppName"]
            )
            #print(response)
            running_instances.append(
                {
                    "AppArn": response["AppArn"],
                    "DomainId": response["DomainId"],
                    "UserProfileName": response["UserProfileName"],
                    "Status": response["Status"],
                    "InstanceType": response["ResourceSpec"]["InstanceType"],
                    "CreationTime": str(response["CreationTime"]),
                    "LastUserActivityTimestamp": str(response["LastUserActivityTimestamp"]),
                    "SageMakerImageArn": response["ResourceSpec"]["SageMakerImageArn"],

                }
            )
    if "NextToken" in response_apps:
        response_apps = client.list_apps(
            NextToken=response_apps["NextToken"],
            MaxResults=10,
            SortOrder='Ascending',
            SortBy='CreationTime'
        )
    else:
        break

print(running_instances)
keys = running_instances[0].keys()

with open('running_instances.csv', 'w', newline='') as output_file:
    dict_writer = csv.DictWriter(output_file, keys)
    dict_writer.writeheader()
    dict_writer.writerows(running_instances)

You cannot view instance status since these are managed by SageMaker service. You can, however, use the list-apps and describe-app CLI calls to see the apps in service for the user, and work backwards to find the instances that are being used by the user.