Hello,
thank you for the suggestions and for helping understand the difference between dir-cache and vfs-cache. I tested with --vfs-fast-fingerprint --buffer-size=0 and I can access the files much faster now, I will continue testing with other values but is better now. Also, I try not to use --vfs-cache-mode=full, as I don't really want to cache the content of the files. This post (dir cache) has been really helpful too.