might want to check out my summary of the two rclone caches, vfs file cache and vfs dir cache.
your concern only about the vfs dir cache.
https://forum.rclone.org/t/status-about-using-rclone-for-music-storage-playback-in-2021-access-times-improved/27648/34
based on that, i do not think you need to worry too much about your script using too many api calls.
in fact, very few api calls are required.
your script is iterating over the mount, which is really asking rclone to iterate over its in-memory list of files.
so after the first initial scan, rclone has the full list of files.
after that, rclone should not have use api calls to re-scan the entire gdrive structure.
- a new file is added to gdrive
rclone mountusing polling, will notice the new file and update its in-memory list of files.
so next time your script scans, rclone is not even contacting gdrive.
of course, how well that works is based on your rclone mount command?