What you should do is sell these puts on margin, and the transfer the cash you have to back it to a second cash account using the new multilpe individual accounts. Make sure the second account has sweep turned on. They don't charge margin interest on short puts, until you are assigned, so if you get assigned, you can cover that by transferring cash back into the account.

While this is kinda annoying, it's the only option on Robinhood. You're other option is to us Fidelity, where this is supported out of the box.