Here are two league templates for OOTP24 (i assume these work in older versions, too) one is from the earlier version of the file, the second is my current save that just finished the year 2000, there's a Korean league (with better talent fwiw) and an independent league, but the og version doesn't have that. This should let you import the structure in a new league or current save.
Original Womens' MLB template
20-team league with Korea & Indy league