Hello Noriko,
Let me first answer your initial question.
No, it's not possible to restore a backup of an Azure Classic VM to an Azure Resource Manager (ARM) VM. Azure Classic VMs and ARM VMs are different deployment models and are not compatible with each other.
If you are in need of restoring a classic VM from azure backup, we don't have a create a new VM option supported for classic VMs. Hence, you need to take a different route which is to restore the classic VMs with "Restore as disks option" and disk needs to be convert to managed disk and then create VM out of those disks.
Important:
As you may be already aware of the announcement of deprecation of classic VMs. This functionality will be fully retired on September 1, 2023.
How does this affect me?
- As of February 28, 2020, customers who didn't utilize IaaS VMs through ASM in the month of February 2020 can no longer create VMs (classic).
- On September 1, 2023, customers will no longer be able to start IaaS VMs by using ASM. Any that are still running or allocated will be stopped and deallocated.
- On September 1, 2023, subscriptions that are not migrated to Azure Resource Manager will be informed regarding timelines for deleting any remaining VMs (classic). Hope this helps! If you have any further questions at all, please let me know in the comments. If the answer provided by has helped, please 'Accept as Answer' and Upvote using "Thumbs-up" so that it can improve discoverability for others in the community looking for help on the same topic.