Unchecked folders will be REMOVED from your file system

If I understand this post, you are saying that once I create a sync folder connection, the Nextcloud Box takes over as the master and the client becomes a slave of the master? If that is the case, how would you sync a folder while excluding certain folders inside that one folder? Let’s say I have a folder in my main data share with a lot of DVD ISO images. I don’t want to fill up my Nextcloud Box storage with all that data, since I could if I needed to recreate those ISO’s at will.

Again I want to stress, this CANNOT be the way this works, or users will be losing files constantly and won’t know why. NO WAY any solution should remove local files. The LOCAL files should ALWAYS be the master.