I am talking from experience.

It doesn't matter if its old project or not, even some older altcoins are better in your bags than new crypto projects, old projects have proven themselves, like Doge coin and Litecoin, you have no problem trusting them and holding for long, but new coins are even more risky.

Many altcoins have died in a very short time after Bitcoin lost the 70k support, and some are already struggling to stay alive, not all altcoins have enough funds to keep their projects up and running while Bitcoin is facing big bloodbath.

It is better to invest most of your funds in Bitcoin and diversify into good projects with great teams backing them up and make sure they raised enough funds too, because many good projects died in the past even while they gave good team but lack some funds.