Hello ! Perhaps my question has already been, I apologize in advance
Interested in the question of access rights to the mounted disk on Windows.
You need to make sure that the mounted disk is not available to the group, for example Users.
I mount the System under the user.
I will explain in more detail:
I am mounting a Google Drive on Windows - how can I restrict access to a group Users?
I mount from the "System" user, as there are several users in the Administrators group
You can control the user/owner and the group of the mount by adding -o UserName=<value> and/or -o GroupName=<value> to your mount command. E.g. -o GroupName="Authenticated Users".
Oh yes, you also have the option -o umask=MASK where you can set permission using umask octal notation. So by finding a suitable combination of user (owner), group and umask you should be able to achieve what you want?
Example: Setting -o umask=077 means only the owner get access. You will always see an entry for "Everyone" as well, but it will only have a few special permissions ("Read attributes", "Read extended attributes" and "Read permissions"), and will not have access to read/write any files (there is an issue to get rid of it).
There are also options -o create_file_umask=MASK and -o create_dir_umask=MASK to set the umask of any new files/directories created, but unless you have very specific requirements for this I wouldn't bother.
I see you figured it out yourself, before I managed to complete my reply..
(Not sure exactly which is better of --file-perms/--dirs-perms and -o umask. I see there is documented an rclone option --umask as well, but it is not supported on Windows, and one has to set umask via WinFsp/FUSE option -o umask)