Buy bitcoin.
This is the best recommendation that you will here from everyone if you're really for the long term. You're at the right hands if you're going to choose bitcoin before any other altcoins.
It's a saver for everyone's portfolio when most alts are down.
I would go out of a limb here and tell op to NOT buy bitcoin.
Why? Because I'm not for investing in things you don't understand. And if it's the case that OP doesn't have any bitcoin, it's highly likely that he/she doesn't understand it in the first place. I think it's highly unlikely for a person to understand bitcoin, and not think it's a good investment.
He suggested cake, sol and other altcoins.
That gives the idea that he understands cryptocurrencies as he understands those altcoins so he understands what bitcoin is. But yeah, if he don't understand it.
He should stay to what he understand but that's just a recommendation if he wants to listen to suggestion.