IMO, you should diversify your crypto assets into several alts that you believe in, if you are able to classify trending and long-term assets then why not divide your capital to invest in both.
But maybe if we invest in trending altcoins then you have to have reasonable expectations and you have to be able to sell and buy at the right time, because it will affect you, a coin can just disappear and have no value at all, so that's what it is. The worry about buying trend coins is that managing the risk profile is more difficult, but why not try your luck on trend altcoins. Still today I think we are still not too late for some altcoins that can lead to the next bull season, in areas as big as AI, metavers still have value, and in the network section like LINK/PYTH I think it needs to be considered.
investing in both is good but sometime I see it as a somewhat ineffective way to invest, we trying to get best of both worlds, but will also get worst of both worlds if we are not careful, I think OP here just trying to find the best most profitable way to invest and its whether based on trend or long term, indeed in trend we can get some good profit just within short amount of time because everyone else is doing the same investing in that kind of project so it matters whether we are early or not, meanwhile with long term, the project is judged by the long term progress, whether it dumps or it didn't currently doesn't matter that much because its for long term.
in my opinion i'd instead pursue for the trend if i want easy quick profit meanwhile long term if i got big capital because its easier to avoid the risk of losing money as well as still making some profit at the end of the day, its just the time frame is longer.
needs also to know that some trend aren't gonna be lasting forever, many time we might think its the right time to join a trend but in reality, its not really the right time because most of the time when a trend is already widespread among many people, its already an outdated trend. so thats need to be paid an attention.