Recently trying to migrate from the cache(beta) to vfs and not entierly sure what's causing my issue here. But basically, within minutes i get the 403 quota error for my files. I have a Plex server pointing to my gdrive, and using the old cache method, i never hit any quota errors.
You have a 50GB cache size and a 10GB read ahead and a huge buffer size.
I'd remove:
--vfs-read-ahead 10G --buffer-size 256M
The old cache worked on chunks.
The new system works on sparse files. If you stream a 60GB file, you need 60GB to store it. If you stream 5x60GB files at the same time, you really need 300GB of cache.
You need to have space to hold at least what you plan to stream concurrently as a baseline as it'll use that space. In reality, you probably want more so it takes advantage of the cache.
The new one uses a service account, which had some changes too so that might be an issue as well.