I copied 2TB of data on an exfat disk from a dying Mac. Then on Windows this data is (almost) missing - eviltoast

I have an old mac with a dying hfs hdd with failing SMART. I copied 2tb of data on an exfat drive but windows only sees only 3 directories and 80gb. Where’s my other stuff? Now after I did that long copy session that lasted a whole day, the disk died from stress and the mac doesn’t boot anymore. Even if it boots, i don’t think the disk can last another full copy session…

Testdisk can show the data, there’s a way to tell windows that the files are there?