autosaving MS office files being saved to iCloud, not to OneDrive

office 365 user.

excel files are kept in iCloud folder on MacBook, and are saved to iCloud.

the "turn on autosave by default" option in excel preferences is turned on.

however, auto saved is not working. it does not save the file every 5 or 10 minutes. i have to save files manually, only then is the latest version of the file visible on other signed into iCloud devices like iPhone and iPad. if i forget to save a file and close the MacBook lid, the latest version of the file is not visible later on iPhone and iPad.

i read that the autosave feature only works when files are being saved to OneDrive, and does not work at all when files are being saved to any other cloud service.

1) is this correct?

2) what other options do we have to periodically keep saving MS office files being saved on iCloud as we are working on them on MacBook?