How to recover a deleted folder?

[tajvdz]

I don't know if I ask my question in the right section. I have a question about getting back a deleted folder.
I have a disk in my AS1004T that gave S.M.A.R.T. errors. It is a 3 TB disk and I wanted the data on a larger disk anyway. So I transfered the data in windows from the old disk to the new disk. I moved it in blocks. I moved the files that I copied to another folder. At the end all files were in the new folder and also on the new disk. The original folder looked empty. I decided to delete (shoft-delete) the empty folder but in the pop up it showed that it was removing 8 files. I think those were hidden files. If it was a disk in my pc I was able to use recovery software but that doesn't work on netweork drives. How is it possible to recover this deleted folder? In my nas software I don't have the recycle bin in use and also no backup. I deleted the folder in windows. Maybe it isn't possible to all to get deleted files \ folders back from an ext4 disk.
Maybe those files are not important but I want to know what it was. I can remove the disk from my nas if possible because I don't need it there anymore. So can someone please give me some advise on what to do? If it is better to ask this question in another section of the forum please tell me as well!