Saris parent
It can do that just fine with the new permissions, you just can't sync the root folder or Downloads folder which is OK as documents, audiobooks, etc would be stored in their respective folders and not Downloads.
You mean that that's ok for you. Which is fine. It isn't ok for other people, which is also fine.
Some people may not want to have to reopen Nextcloud any time a new directory appears on their device so they can add it to Nextcloud, while the other American bigtech backup apps can just pick it up automatically no problem.