The Liquidity pouring into BTC will eventually start pouring into top altcoins and we can already see it happening with likes of $SOL , LINK , $INJ etc making massive moves !
The obvious play here is to learn and leverage on top altcoins to buy
That's always what should be done when someone enters the market, those who think they are okay with just Bitcoin and they shouldn't venture into altcoins, are not doing things the right way because even though there is no doubt that Bitcoin is the best cryptocurrency and it undoubtedly deserves the first spot in your portfolio, but that doesn't mean other cryptocurrencies are useless and they are not worth investments or to be in anyone's portfolio.
So, without a doubt, the best thing one can do is to do some research and buy and add the best altcoins into their portfolio because diversification can provide great returns in most cases where the person has added useful cryptocurrencies in their portfolio and didn't just pick some coins randomly.