How to encrypt existing data on ACD?

Very basic question probably but I do have already around 20TB of data on ACD that I would like to secure by encrypting it … Yes I know I should have done it day 1 but too late … I will be using my Hertzner server to do the job but how can I do this ?
thanks a lot in advance !
PS: it would be a great great advantage if I would have the unencrypted data exposed using the exact same path as today since it would avoid having to regenerate all libraries and metadata in plex …

Sorry for the very dumb question. I found the answer myself in an old forum post.