Does rclone mount download or use data?

rclone mount will not upload/download data on its own.
you would have to copy something to/from the z: drive.

but can use api calls to read the folder names and file names and some meta data like timestamps
https://rclone.org/commands/rclone_mount/#vfs-performance

windows file explorer, needs some tweaks to work well.
you can read more about it here
Looking for a fast and pleasant way to explore my mounted Google Drive - #7 by asdffdsa

for what it is worth, i have not used windows file explorer in 10+ years.