Autosave locallly with Word 2021 Mac?

That is the problem- AutoSave could have been engineered to save and retrieve files from any cloud service - the storage layer could have easily been abstracted from MS apps AutoSave.

It was a marketing decision- not a tech decision - which has impacted users heavily invested in other cloud storage. Hopefully MS will reconsider.

Note that the topic of this thread is a matter of automatically saving locally, not to other remote servers so this reply is not relevant.

Never the less, if that were the case why does AutoSave not save locally on Windows OS, either?

Please document this & help others understand how you came to have insight into the corporate Microsoft development & decision-making processes. And how has the availability of the feature to save Microsoft Office documents to Microsoft's own servers "impacted users" who choose to use other services?

And why doesn't Apple implement it for their proprietary apps or automatically save to anything? Why do Google apps not automatically save to iCloud?

Your reference to 5 minute intervals suggests that you are confusing AutoSave with AutoRecover. They are 2 completely separate & independent features. This is a common misunderstanding exacerbated by articles on the internet from others who don't know the difference, themselves.

As Diane wrote, AutoSave is supported only on OneDrive & SharePoint locations. It cannot work with locally saved files or files saved to other devices. It also is a new Office-wide feature introduced with recent releases of Office.

AutoRecover has been a standard feature for decades but works only for files saved to the startup HD. It does not save to the working file. It is designed & intended to help recover unsaved changes in the event of a critical failure by writing to a separate temporary file but cannot always do so. Under normal circumstances the temporary file is deleted when you close the file to which it pertains. It should not be considered as an automatic save or backup feature.