Recycle Bin Option for RN10400?

On OS6 there is the snapshot feature which unlike the Recycle Bin feature on older ReadyNAS isn't limited to just using the SMB protocol (though this is less of an issue now that SMB is the preferred protocol for Macs not just for Windows). However the minimum interval for automatic snapshots is hourly so they won't help if you need to recover a file as it was at some point since the most recent snapshot if that is different to how it was when the most recent snapshot was taken.

You must have missed it, but there is the Idea Exchange for ReadyNAS Network Storage where you can make product suggestions and upvote ones made by others. You may wish to request that we add the Recycle Bin feature there.

Support does have support contracts available for purchase if you wish to extend your support. Alternatively you can seek help on the community here.

Support should be able to pass on feature requests without requiring a contract, but the Ideas Exchange is monitored regularly and posting suggestions there should be enough. The more popular a suggestion is the more likely it is to be implemented.