You can perform backup to URL to later restore on another Managed Instance.
BACKUP DATABASE [XXXXXXX]
TO URL = 'https://XXXXXX.blob.core.windows.net/XXXXX/XXXX_20200424.bak'
WITH COPY_ONLY
RESTORE DATABASE [XXXXXX] FROM URL='https://XXXXX.blob.core.windows.net/XXXX/XXX_backup_2021_01_29_130404.bak'
You can also use Azure CLI.
az account set --subscription "Enter Subscription ID"
az sql midb restore -g Source_Resource_group --mi Source_instance_name
-n Source_database_name --dest-name Destination_database_name
--time "2022-11-09T11:30:00" --dest-mi Dest_instance_name
--dest-resource-group dest_resource_group