Hi, I just tested this. S23U to Tab S9 Ultra. Using Samsung file manager. Using a folder physically stored on the S23U (internal storage), it xfered across and was received by the Tab S9 Ultra as a folder with same name and with all files intact. Even worked the other way.
However, if I choose a folder that is stored in the cloud (albeit still in Samsung file manager), then only the files are xfered ( into a folder named Quick Share).
In light of this, can you check the source of the folder you want to xfer. If it's physically stored in the phone, it should be okay, but if linked to the cloud, then maybe not?