I never have any dilemma about to choose bitcoin or altcoins because I do always have separate funds for altcoin investments like 80% of my available funds are for buying bitcoins at dips and the remaining 20% is alone for altcoins and I do hold more than 10 altcoins right now.
If someone think that price of bitcoin will go further down from here and its still risky to buy bitcoin at current price then he should start doing DCA Dollar Cost Averaging. Its very obvious that we dont know whats the bottom. We wake up someday and see that price of bitcoin is rising, its late to buy bitcoin by then.
For me bitcoin is the only choice of investemnt when it comes to crypto. There is no need to invest in alts as they go up only when bitcoin goes up. So its better to keep your investment to bitcoin only.