Yes.
The most direct reason being that Unraid allows you to use any combination of hardware that you wish, and it's up to you to configure and customize that hardware to meet your needs. There is no possible way to back up Unraid such that it will always restore to an unknown set of hardware with all containers and VM's functioning identically.
What you are asking would only be possible if Unraid controlled every piece of the machine, allowing you to use only a specific tested combination of hardware.
Now, you say, I don't care about different hardware, I just want to be able to restore back to my own hardware exactly as I backed up. That scenario is covered already, and has been for years. File level copies of all drives taken with the services stopped is all that is necessary, it's always been that way.
Making valid backups with services still running ranges from tricky to impossible, as has been covered multiple times in this thread and elsewhere.