downloads from google drive disappear

Under Normal operations - files downloaded will appearing in the Downloads folder appearing in the Dock of this computer

That is unless the user has purposely change the location from Downloads to another location on the computer

The icon just Left of Trash ( Bin )

In which case, the previous suggestion should help

One thing you can do is to download and install the free Find Any File app. Then when you download, note the filenames. Once the files are downloaded, use FAF to locate them.

https://apps.tempel.org/FindAnyFile/