Depends on your preferences I guess? Of course if you exclude shitcoins or those useless token that appears out of thin air, choosing which crypto to invest in depends on what project you believe in, but mostly, people chose bitcoin as it is the safest option out there especially for newbies.
For me as an example, majority of my portfolio is heavily invested in bitcoin because of how briliant the technology it offers, it is also a multifaceted tool that will serve as your gateway down the rabbit hole when it comes to programming, security, privacy and economics(finance). Moreover, less than 10% of my portfolio is in ETH and XMR as I think that ETH could offer a lot of opportunies in Defi/GameFi while Monero is for privacy related stuff.
Besides preferences, one important matter is your financial capabilities and your risk tolerance.