I saw a youtube of an Australian (?) guy who divided his lemon grass just like you’d divide anything else. Separate the roots and put 2-3 plants into small pots (he was potting it up to sell) and give them haircuts. Eventually they ended up in 5 gallon buckets. Rinse and repeat.
Ok, that sounds doable. I’ve got a couple neighbors/friends who want some lemongrass. Mine is a hunk of blades about 1’ in diameter now. Definitely big enough, IMHO, to divvy up 3 or 4 different ways. And the resulting hunks would be bigger than the one I started with last April.