There is Bitcoin & everything else is a shitcoin. Sure you can make big fiat gains in Altcoins if you’re lucky but none of them have the longevity, decentralization & proof of work like Bitcoin. I wouldn’t park a big portion of my net worth in any Altcoin long term. Short teem is fine but not long term.
Bitcoin is proven to survive many bear market and still continue to make a new high every bull cycly so holding it is better than altcoin.
While altcoin can give higher profit in terms of percentage, holding it for long term doesn't guarantee you profit but instead carries a higher risk because you are not sure if they will pump again after bear market.
In the end, bitcoin will always be the best cryptocurrency to hold.
They are not as predictable as BTC, because with BTC, cycles dictate the dominance, though even they are not concrete and may change due to many factors at hand.
So the biggest take is to have as much BTC as you can, others - if you want to diversify and see what sticks.