If you’re ok with sacrificing an onion, I say let the leaves grow just a little more and then start using them in food you eat! Green onions are really just a selectively bred species of onion where the leaves are the focus, so they taste just a little better than regular onion leaves, though regular onion leaves still taste great! I had a sprouting onion a few weeks ago that supplied me with fresh onion leaves for at least two weeks before I decided the onion needed to be thrown out, at-
-which point I cut the leaves off and stuck them in the fridge to finish off later. They’re really just an easily accessible fresh herb since you don’t need to provide soil, water, or ample sunlight and it’s right there in your kitchen. If you don’t want to sacrifice the onion though, I’d use it as soon as possible. Once an onion starts sprouting, it starts getting mushier layer by layer and quickly gets really gross, really bad if you want to eat the onion itself rather than letting it supply-