So in short, if you want to diversify your portfolio, other than btc, better choose the very top alts like ETH or BNB. So even if btc is down, we all know that most of the time, the top alts can survive and may even rise on their own, depending on their actual developments. But most of the alts will go down the drain especially those that are created for the mere purpose of devs' pockets.
But i'm surprised with how ethereum and BNB performing these days because they are not even much affected with how the market goes. In this case, ethereum might probably overtake bitcoin's performance seeing its consistent positive price.