Most folks run a rc command after the mount happens to prime the directory listing:
ExecStartPost=/usr/bin/rclone rc vfs/refresh recursive=true --rc-addr 127.0.0.1:5575 _async=true
My rc runs locally on 5575 and it will run much faster than a find.
I wouldn't touch attribute timeout unless you are certain nothing else is touching a file anywhere else.
Dir cache can be set very high on polling remotes like Google Drive, Dropbox, etc.
# Dropbox is a polling remote so this value can be set very high and any changes are detected via polling.
--dir-cache-time 9999h \