Why are my Excel files not saving to desktop on iMac?

Sorry how long this post is. Lost much of a week's Excel work this weekend. Daily use of the worksheet is on a MBAir (Sequoia, up to date). To finish the work up, the worksheet is AirDropped onto the bigger-screen iMac (Ventura). When complete, I send it back to the MBAir for the next week. This week, what opened on the Air was not what I'd sent over - it was a week old. And when checking on the iMac, that was now the old worksheet too. The new version seems to be gone.

In testing things, I created a sample Excel file on the Air and saved to desktop. No file image. Tried again - nothing. I assume it's somewhere. Then tried to "Move" another Excel file - Desktop's not a listed option.

In Excel Recents, there the worksheets are - Users/(me)/Library/Mobile documents/iCloud Drive/Desktop.

I just want to save things to the desktop, as per years and years of use.

I'll grant I'm missing something here - any suggestions welcome!

[Re-Titled by Moderator]