Is it possible to recover deleted items?

I have accidentally deleted a whole folder. Is it possible to recover the folder through the Cryptomator app or Google Drive?

Cryptomator does not offer a recycle bin.
There may be a workaround (at your own risk. Do your Backups!)

If you know when you have deleted the files, you can search in the recycle bin of your google drive for encrypted files and folders matching this timestamp and restore the encrypted data and hope that all necessary files are restored to get your decrypted files in the vault back.

Please keep in mind that this is not a 100% safe workaround. You may cause inconsistency in you vault and should check it afterwords with the sanitizer tool.
Please read this as well: decrypt the encrypted file name

And I have to admit that I’m not sure if goggle drive offers the recycle bin for files that are deleted via a connected app. Maybe they offer this function only for files deleted via the browser interface or their desktop app (I actually do not use google drive)

You should be able to restore the folder at https://drive.google.com/drive/trash

I just deleted a folder and this is what’s in my trash now:

Make sure to restore both the so-called directory file (begins with a 0 in its filename and usually has 36 bytes) and the encrypted directory itself. If you let Google Drive restore these (select them, right-click, and “Restore”), they will automatically be put back into the originating path so that Cryptomator will be able to detect them properly.