Checked RAID stripe size and it was 64kb, formatted as ntfs 4kb, and restored some data. Looks like it's normal sizes:
Size: 2.68 TB (2,947,426,839,102)
Size on disk: 2.68 TB (2,947,816,177,664)
Reformatted again with a new veracrypt key which will take another 13 hours (whole disk...