Yes, you can withdraw BNB-BNBX-LP from Ellipsis.finance. The LP tokens are ERC-20 tokens and are held in your wallet. You can withdraw them just like any other ERC-20 token. All you need to do is open your wallet, select the token you want to withdraw, enter the amount, and then click send. Your LP tokens will be sent to your wallet and you can then use them as you wish.