You're still in legal status if your I-94 date hasn’t expired

The visa is just for entry; I-94 governs your allowed stay

You don’t need to renew the visa unless you leave and re-enter the U.S.

If your visa expires but your I-94 is still valid, you may stay in the U.S. lawfully until the I-94 expiration date.

But if you leave the U.S., you cannot reenter without a valid visa, even if your I-94 is still active.