And nsec.app on your devices will be woken up by push API when any app wants to access the keys. If all your devices are offline then it won't respond. For business use case I'd suggest trying our hosted version - install it on your office server/umbrel etc with docker and it will be always online.
Discussion
Do you have docs on the docker setup?
There's only this: https://github.com/nostrband/noauth#running-hosted-version-with-docker