Hi,
When using PsShutdown, there is limitation that aborts a shutdown (only possible while a countdown is in progress).
https://learn.microsoft.com/en-us/sysinternals/downloads/psshutdown
Moreover, here is command to abort the shutdown process on remote machines using a csv file of server names, you could modify based on your request and have a try.
https://community.spiceworks.com/topic/1998972-abort-shutdown-remotely
Please note: Information posted in the given link is hosted by a third party. Microsoft does not guarantee the accuracy and effectiveness of information.
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Hope this helps and please help to accept as Answer if the response is useful.
Thanks,
Jenny